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    Biguanide and Thiazolidinedione (Glitazone) Antidiabetic Combinations

    BOXED WARNING

    Acute heart failure, acute myocardial infarction, angina, cardiac disease, cardiogenic shock, edema, heart failure, myocardial infarction, peripheral edema, pulmonary edema

    Metformin; rosiglitazone is contraindicated in patients with pre-existing New York Heart Association (NYHA) Class III or IV heart failure and is not recommended for use in patients with symptomatic or acute heart failure; further, use this medication with caution in patients with other cardiac disease. Acute decompensation in cardiac status (i.e., acute heart failure, cardiogenic shock, or acute myocardial infarction) characterized by hypoxia has been associated with the development of acidosis in patients taking metformin. Furthermore, thiazolidinediones, including rosiglitazone, when used alone or in combination with other antidiabetic agents, can cause or exacerbate congestive heart failure. Patients should be carefully observed for signs and symptoms of heart failure including excessive, rapid weight gain, dyspnea, and/or edema (peripheral edema, pulmonary edema) after drug initiation and changes in dose. If these signs and symptoms develop, the heart failure should be managed according to current standards of care. Discontinuation or dose reduction of rosiglitazone must be considered. The incidence of heart failure associated with rosiglitazone use is higher in those patients receiving concomitant insulin therapy, receiving higher doses of rosiglitazone, and who have risk factors for congestive heart failure ; the incidence of myocardia ischemia and angina may also be higher in patients taking rosiglitazone with insulin. The manufacturer recommends that insulin and rosiglitazone not be used concomitantly. In addition, older patients and those with a longer duration of diabetes experienced a higher incidence of cardiovascular event during clinical trials. Dose-related weight-gain has been reported in patients treated with rosiglitazone therapy. Patients who experience rapid increases in weight should be evaluated for fluid accumulation and volume-related events such as excessive edema and heart failure. While an increased risk of heart failure with rosiglitazone use has clearly been established, data supporting an increased risk of other types of cardiovascular events are inconclusive. Safety data from 2 meta-analyses of controlled clinical trials have shown that there is a potentially significant increase in myocardial infarction (MI); one also indicated a trend towards an increase in heart-related deaths in patients taking rosiglitazone versus other antidiabetic agents or placebo. Other published and unpublished data from long-term clinical trials, including an interim analysis of data from the RECORD trial (a large, ongoing, randomized open label trial) and a large, prospective observational study provide contradictory evidence about the risks in patients treated with rosiglitazone. In order to provide more conclusive data on the risk of MI in patients receiving rosiglitazone, the FDA implemented a comprehensive expert re-evaluation of the results from the RECORD trial; the re-evaluation confirmed the original RECORD finding that did not show an increased risk of MI associated with rosiglitazone. During the re-evaluation, a total of 184 cardiovascular or unknown-cause deaths (88 rosiglitazone, 96 metformin/sulfonylurea), 128 participants with an MI (68 rosiglitazone, 60 metformin/sulfonylurea), and 113 participants with a stroke (50 rosiglitazone, 63 metformin/sulfonylurea) were included. The hazard ratio for rosiglitazone versus metformin/sulfonylurea for the end point of cardiovascular (or unknown cause) death, MI, or stroke was 0.95 (95% CI 0.78%, 1.17%) compared with 0.93 (95% CI 0.74%, 1.15%) for the original RECORD results. Treatment comparisons for MI (HR 1.13, 95% CI 0.80%, 1.59%) and mortality (HR 0.86, 95% CI 0.68%, 1.08%) were also the same compared with the original RECORD results. The results of the RECORD trial support the findings of 2 earlier long-term, prospective, randomized, controlled clinical trials (each trial more than 3 years; total number of patients = 9,620). In patients with impaired glucose tolerance, although the incidence of cardiovascular events was higher among subjects who were randomized to rosiglitazone in combination with ramipril than among subjects randomized to ramipril alone, no statistically significant differences were observed for major adverse cardiovascular events and its components between rosiglitazone and placebo. In patients with type 2 diabetes who were initiating oral agent monotherapy, no statistically significant differences were observed for major adverse cardiovascular events and its components between rosiglitazone and metformin or a sulfonylurea. Some uncertainty over the cardiovascular safety of rosiglitazone nevertheless remain, and thus close monitoring is prudent in the rosiglitazone treated patient, especially among patients with a greater risk for cardiovascular events.

    Acidemia, hypovolemia, hypoxemia, lactic acidosis, metabolic acidosis, sepsis

    Metformin; rosiglitazone is contraindicated in patients with metabolic acidosis. Metformin is associated with an increased risk for lactic acidosis. Lactic acidosis should be suspected in any diabetic patient with metabolic acidosis lacking evidence of ketoacidosis (ketonuria and ketonemia). Lactic acidosis is a rare, but serious complication that can occur due to metformin accumulation and is fatal in approximately 50% of cases. Lactic acidosis may also occur in association with a number of pathophysiologic conditions, including diabetes mellitus, and whenever there is significant tissue hypoperfusion and hypoxemia or significant renal dysfunction. Certain medications that are eliminated via the kidney when used concomitantly with metformin may also increase the risk of lactic acidosis. Acute heart failure, cardiogenic shock, or acute myocardial infarction and other conditions characterized by acute hypoxia have been associated with the development of lactic acidosis and may cause prerenal azotemia. To reduce the risk of lactic acidosis, metformin; rosiglitazone should be promptly withheld in the presence of any condition associated with hypoxemia, hypovolemia, or sepsis. Lactic acidosis is characterized by elevated blood lactate levels, acidemia, electrolyte disturbances, an increased anion gap, and an increased lactate/pyruvate ratio. When metformin is implicated as the cause of lactic acidosis, metformin plasma levels more than 5 mcg/mL are generally noted. The reported incidence of lactic acidosis in patients receiving metformin is very low (approximately 0.03 cases/1,000 patient-years). A nested case-control study of 50,048 patients with type 2 diabetes mellitus demonstrated that during concurrent use of oral diabetes drugs, there were 6 identified cases of lactic acidosis. The crude incidence rate was 3.3 cases per 100,000 person-years in patients treated with metformin; it should be noted that all of the subjects had relevant comorbidities known to be risk factors for lactic acidosis. The onset of lactic acidosis often is subtle, and accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, increasing somnolence, and nonspecific abdominal distress. There may be associated hypothermia, hypotension, and resistant bradycardia with more marked acidemia. The patient and the prescriber must be aware of such symptoms and the patient should be instructed to notify the physician immediately if they occur. Metformin should be withdrawn until the situation is clarified. Serum electrolytes, ketones, blood glucose, and if indicated, blood pH, lactate levels, and even blood metformin levels may be useful.

    DEA CLASS

    Rx

    DESCRIPTION

    Oral combination of metformin, a biguanide, and rosiglitazone, a thiazolidinedione (TZD)
    Used in adults for type 2 diabetes mellitus; rosiglitazone is not to be used with insulin
    Risk of lactic acidosis due to metformin is low; TZDs may cause or exacerbate heart failure; monitor closely

    COMMON BRAND NAMES

    Avandamet

    HOW SUPPLIED

    Avandamet Oral Tab: 2-1000mg, 2-500mg

    DOSAGE & INDICATIONS

    For the treatment of type 2 diabetes mellitus not controlled by diet and exercise.
    For use when initial treatment with metformin alone does not result in adequate glycemic control.
    Oral dosage
    Adults

    Usual starting dose: 4 mg/day rosiglitazone plus the dose of metformin already being taken. For patients taking metformin 1,000 mg/day PO, give 1 tablet of rosiglitazone 2 mg/metformin 500 mg PO twice daily. For patients taking metformin 2,000 mg/day PO daily, give 1 tablet of rosiglitazone 2 mg/metformin 1,000 mg PO twice daily. If additional glycemic control is needed, the daily dose may be increased by increments of 4 mg rosiglitazone and/or 500 mg metformin. After an increase in metformin dosage, may titrate if patients are not adequately controlled after 1 to 2 weeks. After an increase in rosiglitazone dosage, dose titration is not recommended until 8 to 12 weeks. Max: 4 mg rosiglitazone with 1,000 mg metformin PO twice daily. Generally, elderly patients should not be titrated to the maximum dose. Rosiglitazone use is not recommended in patients with symptomatic heart failure. In patients with NYHA Class III or IV congestive heart failure, use is contraindicated. When using rosiglitazone in patients with or without symptomatic heart disease and diabetes, monitor closely for signs of weight gain, peripheral edema, or congestive heart failure. The risk of these symptoms is increased when higher doses of rosiglitazone are used in combination with insulin in patients at risk for heart failure. Discontinue rosiglitazone if any deterioration in cardiac status occurs.

    For use when initial treatment with rosiglitazone alone does not result in adequate glycemic control.
    Oral dosage
    Adults

    The usual starting dose is 1,000 mg/day of metformin plus the dose of rosiglitazone already being taken. For patients taking rosiglitazone 4 mg/day PO, give 1 tablet of rosiglitazone 2 mg/metformin 500 mg PO twice daily. For patients taking rosiglitazone 8 mg/day PO, give 1 tablet of rosiglitazone 4 mg/metformin 500 mg PO twice daily. If additional glycemic control is needed, the daily dose may be increased by increments of 4 mg rosiglitazone and/or 500 mg metformin. After an increase in metformin dosage, may titrate if patients are not adequately controlled after 1 to 2 weeks. After an increase in rosiglitazone dosage, dose titration is not recommended until 8 to 12 weeks. Max: 4 mg rosiglitazone with 1,000 mg metformin PO twice daily. Generally, elderly patients should not be titrated to the maximum dose. Monitor closely for signs of weight gain, peripheral edema, or congestive heart failure. The risk of these symptoms is increased when higher doses of rosiglitazone are used in combination with insulin in patients at risk for heart failure. Discontinue rosiglitazone if any deterioration in cardiac status occurs.

    Switching patients already taking rosiglitazone plus metformin to the combination product.
    Oral dosage
    Adults

    The usual starting dose is the dose of rosiglitazone and metformin already being taken by the patient. Titrate as needed to clinical goals. May titrate by 4 mg rosiglitazone and/or 500 mg metformin. Max: 4 mg rosiglitazone with 1,000 mg metformin PO twice daily. Generally, do not titrate the elderly to the maximum dose. Monitor closely for signs of weight gain, peripheral edema, or congestive heart failure. The risk of these symptoms is increased when higher doses of rosiglitazone are used in combination with insulin in patients at risk for heart failure. Discontinue rosiglitazone if any deterioration in cardiac status occurs.

    MAXIMUM DOSAGE

    Adults

    8 mg/day PO rosiglitazone with 2000 mg/day PO metformin.

    Elderly

    In general do not titrate to the adult maximum dosage of 8 mg/day PO rosiglitazone with 2000 mg/day PO metformin.

    Adolescents

    Safety and efficacy have not been established.

    Children

    Safety and efficacy have not been established.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    Because impaired hepatic function may significantly limit the ability to clear lactate, metformin should generally be avoided in patients with clinical or laboratory evidence of hepatic disease. Avoid initiating rosiglitazone in patients with hepatic impairment where the ALT is greater than 2.5 times the upper limit of normal.

    Renal Impairment

    eGFR more than 45 mL/minute/1.73 m2: No dosage adjustment needed. Obtain an eGFR at least annually in all patients taking metformin.
    eGFR 30 to 45 mL/minute/1.73 m2: Initiation of rosiglitazone; metformin is not recommended. Obtain an eGFR at least annually in all patients taking rosiglitazone; metformin. In patients whose eGFR is initially greater than 45 mL/minute/1.73 m2, and then later falls below 45 mL/minute/1.73 m2, assess the benefits and risks of continuing treatment. Discontinue rosiglitazone; metformin if the patient’s eGFR later falls below 30 mL/minute/1.73 m2. The ADA and others suggest it is reasonable to decrease the dose by 50% (or use one-half the maximum recommended dose) and monitor renal function every 3 months in those with an eGFR less than 45 mL/minute/1.73 m2. Do not initiate the drug in patients at this stage. Additional caution is required in patients with anticipated significant fluctuations in renal status or those at risk for abrupt deterioration in kidney function, based on previous history, other comorbidities, albuminuria, and medication regimen (e.g., potent diuretics or nephrotoxic agents).
    eGFR less than 30 mL/minute/1.73 m2: Use of metformin; rosiglitazone is contraindicated.
     
    Intermittent hemodialysis
    Use of metformin; rosiglitazone is contraindicated. Metformin is dialyzable; hemodialysis will efficiently remove accumulated metformin in the case of drug-induced lactic acidosis, provided metformin administration is halted..

    ADMINISTRATION

    Oral Administration

    Administer metformin; rosiglitazone combination tablets with meals.

    STORAGE

    Avandamet:
    - Store at 77 degrees F; excursions permitted to 59-86 degrees F

    CONTRAINDICATIONS / PRECAUTIONS

    General Information

    NOTE: This monograph discusses the use of metformin; rosiglitazone for the management of type 2 diabetes. Clinicians may wish to consult the individual drug monographs for more information.
     
    Metformin; rosiglitazone is contraindicated in patients who have a known metformin or rosiglitazone hypersensitivity, or a known or suspected allergy to any of the inactive ingredients.

    Diabetic ketoacidosis, type 1 diabetes mellitus

    Metformin; rosiglitazone use is contraindicated in patients with diabetic ketoacidosis (DKA), with or without coma; DKA should be treated with insulin. This combination is not intended for the treatment of type 1 diabetes mellitus. No studies have been performed in patients with type 2 diabetes previously treated with other oral hypoglycemics and switched to Avandamet. Patients undergoing changes in diabetic therapy should be monitored for fluctuations in glycemic control.

    Acute heart failure, acute myocardial infarction, angina, cardiac disease, cardiogenic shock, edema, heart failure, myocardial infarction, peripheral edema, pulmonary edema

    Metformin; rosiglitazone is contraindicated in patients with pre-existing New York Heart Association (NYHA) Class III or IV heart failure and is not recommended for use in patients with symptomatic or acute heart failure; further, use this medication with caution in patients with other cardiac disease. Acute decompensation in cardiac status (i.e., acute heart failure, cardiogenic shock, or acute myocardial infarction) characterized by hypoxia has been associated with the development of acidosis in patients taking metformin. Furthermore, thiazolidinediones, including rosiglitazone, when used alone or in combination with other antidiabetic agents, can cause or exacerbate congestive heart failure. Patients should be carefully observed for signs and symptoms of heart failure including excessive, rapid weight gain, dyspnea, and/or edema (peripheral edema, pulmonary edema) after drug initiation and changes in dose. If these signs and symptoms develop, the heart failure should be managed according to current standards of care. Discontinuation or dose reduction of rosiglitazone must be considered. The incidence of heart failure associated with rosiglitazone use is higher in those patients receiving concomitant insulin therapy, receiving higher doses of rosiglitazone, and who have risk factors for congestive heart failure ; the incidence of myocardia ischemia and angina may also be higher in patients taking rosiglitazone with insulin. The manufacturer recommends that insulin and rosiglitazone not be used concomitantly. In addition, older patients and those with a longer duration of diabetes experienced a higher incidence of cardiovascular event during clinical trials. Dose-related weight-gain has been reported in patients treated with rosiglitazone therapy. Patients who experience rapid increases in weight should be evaluated for fluid accumulation and volume-related events such as excessive edema and heart failure. While an increased risk of heart failure with rosiglitazone use has clearly been established, data supporting an increased risk of other types of cardiovascular events are inconclusive. Safety data from 2 meta-analyses of controlled clinical trials have shown that there is a potentially significant increase in myocardial infarction (MI); one also indicated a trend towards an increase in heart-related deaths in patients taking rosiglitazone versus other antidiabetic agents or placebo. Other published and unpublished data from long-term clinical trials, including an interim analysis of data from the RECORD trial (a large, ongoing, randomized open label trial) and a large, prospective observational study provide contradictory evidence about the risks in patients treated with rosiglitazone. In order to provide more conclusive data on the risk of MI in patients receiving rosiglitazone, the FDA implemented a comprehensive expert re-evaluation of the results from the RECORD trial; the re-evaluation confirmed the original RECORD finding that did not show an increased risk of MI associated with rosiglitazone. During the re-evaluation, a total of 184 cardiovascular or unknown-cause deaths (88 rosiglitazone, 96 metformin/sulfonylurea), 128 participants with an MI (68 rosiglitazone, 60 metformin/sulfonylurea), and 113 participants with a stroke (50 rosiglitazone, 63 metformin/sulfonylurea) were included. The hazard ratio for rosiglitazone versus metformin/sulfonylurea for the end point of cardiovascular (or unknown cause) death, MI, or stroke was 0.95 (95% CI 0.78%, 1.17%) compared with 0.93 (95% CI 0.74%, 1.15%) for the original RECORD results. Treatment comparisons for MI (HR 1.13, 95% CI 0.80%, 1.59%) and mortality (HR 0.86, 95% CI 0.68%, 1.08%) were also the same compared with the original RECORD results. The results of the RECORD trial support the findings of 2 earlier long-term, prospective, randomized, controlled clinical trials (each trial more than 3 years; total number of patients = 9,620). In patients with impaired glucose tolerance, although the incidence of cardiovascular events was higher among subjects who were randomized to rosiglitazone in combination with ramipril than among subjects randomized to ramipril alone, no statistically significant differences were observed for major adverse cardiovascular events and its components between rosiglitazone and placebo. In patients with type 2 diabetes who were initiating oral agent monotherapy, no statistically significant differences were observed for major adverse cardiovascular events and its components between rosiglitazone and metformin or a sulfonylurea. Some uncertainty over the cardiovascular safety of rosiglitazone nevertheless remain, and thus close monitoring is prudent in the rosiglitazone treated patient, especially among patients with a greater risk for cardiovascular events.

    Acidemia, hypovolemia, hypoxemia, lactic acidosis, metabolic acidosis, sepsis

    Metformin; rosiglitazone is contraindicated in patients with metabolic acidosis. Metformin is associated with an increased risk for lactic acidosis. Lactic acidosis should be suspected in any diabetic patient with metabolic acidosis lacking evidence of ketoacidosis (ketonuria and ketonemia). Lactic acidosis is a rare, but serious complication that can occur due to metformin accumulation and is fatal in approximately 50% of cases. Lactic acidosis may also occur in association with a number of pathophysiologic conditions, including diabetes mellitus, and whenever there is significant tissue hypoperfusion and hypoxemia or significant renal dysfunction. Certain medications that are eliminated via the kidney when used concomitantly with metformin may also increase the risk of lactic acidosis. Acute heart failure, cardiogenic shock, or acute myocardial infarction and other conditions characterized by acute hypoxia have been associated with the development of lactic acidosis and may cause prerenal azotemia. To reduce the risk of lactic acidosis, metformin; rosiglitazone should be promptly withheld in the presence of any condition associated with hypoxemia, hypovolemia, or sepsis. Lactic acidosis is characterized by elevated blood lactate levels, acidemia, electrolyte disturbances, an increased anion gap, and an increased lactate/pyruvate ratio. When metformin is implicated as the cause of lactic acidosis, metformin plasma levels more than 5 mcg/mL are generally noted. The reported incidence of lactic acidosis in patients receiving metformin is very low (approximately 0.03 cases/1,000 patient-years). A nested case-control study of 50,048 patients with type 2 diabetes mellitus demonstrated that during concurrent use of oral diabetes drugs, there were 6 identified cases of lactic acidosis. The crude incidence rate was 3.3 cases per 100,000 person-years in patients treated with metformin; it should be noted that all of the subjects had relevant comorbidities known to be risk factors for lactic acidosis. The onset of lactic acidosis often is subtle, and accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, increasing somnolence, and nonspecific abdominal distress. There may be associated hypothermia, hypotension, and resistant bradycardia with more marked acidemia. The patient and the prescriber must be aware of such symptoms and the patient should be instructed to notify the physician immediately if they occur. Metformin should be withdrawn until the situation is clarified. Serum electrolytes, ketones, blood glucose, and if indicated, blood pH, lactate levels, and even blood metformin levels may be useful.

    Renal disease, renal failure, renal impairment

    Metformin; rosiglitazone is contraindicated for use in patients with renal failure or severe renal impairment, defined as an estimated glomerular filtration rate (eGFR) below 30 mL/minute/1.73 m2. Initiating rosiglitazone; metformin in patients with an eGFR between 30 to 45 mL/minute/1.73 m2 is not recommended. Before initiation of treatment and at least annually thereafter, obtain an estimated glomerular filtration rate (eGFR) to assess renal function. In those patients at increased risk for the development of renal impairment, such as the elderly, renal function should be assessed more frequently. Metformin is substantially eliminated by the kidney and the risk of lactic acidosis increases with the degree of intrinsic renal disease or impairment. In patients taking rosiglitazone; metformin whose eGFR later falls below 45 mL/minute/1.73 m2, assess the benefits and risks of continuing treatment. Discontinue rosiglitazone; metformin if the patient’s eGFR later falls below 30 mL/minute/1.73 m2. Based on the results of a comprehensive FDA safety review, the FDA concluded that metformin can be used safely in patients with mild renal impairment, and in some patients with moderate renal impairment. The measure of kidney function used to determine whether a patient can receive metformin has been changed from serum creatinine to the eGFR; this is because in addition to serum creatinine concentration, the eGFR takes into account additional parameters that are important, such as the patient’s age, gender, race and/or weight.

    Alcoholism, ethanol ingestion, ethanol intoxication, hepatic disease, jaundice

    Use metformin; rosiglitazone cautiously in patients with hepatic disease. Metformin administration increases the risk for lactic acidosis. Since the liver is important for clearing accumulated lactic acid, metformin is not generally recommended in patients with clinical or laboratory evidence of hepatic disease as the risk of lactic acidosis may be increased. In all patients, measure liver function tests (LFTs) before metformin; rosiglitazone initiation. Do not start rosiglitazone in a patient with clinical evidence of active liver disease or increased serum transaminase concentrations defined as an ALT greater than 2.5 times the upper limit of normal (ULN). Evaluate patients with an ALT concentration of 2.5 times the ULN or less at baseline or during rosiglitazone receipt for the etiology of the increased ALT concentration. In these patients, start or continue rosiglitazone cautiously and closely follow the liver enzyme concentrations. If the ALT concentration increases to greater than 3 times the ULN, recheck the ALT concentration as soon as possible. If the ALT concentration remains greater than 3 times the ULN or jaundice is present, discontinue rosiglitazone. During post-marketing experience with rosiglitazone, hepatitis, hepatic enzyme elevations to 3 or more times the ULN, and hepatic failure with and without fatal outcome have been reported. Hepatic disease also causes altered gluconeogenesis, which may affect glycemic control. Alcohol is known to potentiate the effect of metformin on lactate metabolism. Patients should be warned against excessive ethanol ingestion (ethanol intoxication) while taking metformin due to the increased risk for lactic acidosis. Those with ethanol intoxication are also particularly susceptible to hypoglycemic effects of oral antidiabetic agents. Metformin; rosiglitazone use should be avoided by those patients with alcoholism.

    Diarrhea, vomiting

    Gastrointestinal (GI) side effects are common during the initiation of metformin or metformin; rosiglitazone therapy. However the later occurrence of GI symptoms, are unlikely to be due to usual drug effects and may be due to a change in clinical status and may be due to lactic acidosis (from the metformin component), hepatic dysfunction (from the rosiglitazone component), or other serious disease. Patients stable on metformin; rosiglitazone therapy who complain of an increase in GI symptoms should undergo laboratory investigation to determine the etiology of the GI symptoms. These include, but are not limited to, diarrhea and nausea/vomiting. Furthermore, withholding metformin therapy until the cause of the GI symptoms is known may be necessary. Finally, diarrhea and nausea/vomiting may alter gastric emptying and caloric intake, which could all affect blood glucose control, especially increasing the risk of low blood glucose. Patients should be advised to contact their prescriber if an increase in gastrointestinal symptoms occurs while taking rosiglitazone; metformin and patients should also be advised to monitor their blood glucose concentrations more frequently.

    Radiographic contrast administration

    Discontinue metformin; rosiglitazone at the time of or before radiographic contrast administration in patients with an estimated glomerular filtration rate (eGFR) between 30 and 60 mL/minute/1.73 m2; in patients with a history of hepatic disease, alcoholism, or heart failure; or in patients who will be administered intra-arterial iodinated contrast. Re-evaluate the eGFR 48 hours after the imaging procedure; restart metformin if renal function is stable.

    Burns, dehydration, fever, infection, surgery, trauma

    To reduce the risk of lactic acidosis, metformin should be promptly withheld in the presence of any condition associated with hypoxemia, dehydration, or sepsis. Metformin; rosiglitazone therapy should be temporarily suspended for any surgery, except for minor procedures where intake of fluids and food is not restricted. Do not restart this drug until oral intake is resumed and renal function has been evaluated as normal. Temporary use of insulin in place of oral antidiabetic agents may be necessary during periods of physiologic stress (e.g., burns, systemic infection, trauma, surgery, or fever). Any change in clinical status, including diarrhea or vomiting, may also increase the risk of lactic acidosis and may require laboratory evaluation in patients on metformin and may require the drug be withheld. Prior to initiation or dose escalation of metformin; rosiglitazone, secondary causes of poor glycemic control (i.e., infection) should be evaluated and treated.

    Adrenal insufficiency, gastroparesis, GI obstruction, hypercortisolism, hyperglycemia, hyperthyroidism, hypoglycemia, hypothyroidism, ileus, malnutrition, pituitary insufficiency

    Delayed stomach emptying may alter blood glucose control; monitor patients with diarrhea, gastroparesis, GI obstruction, ileus, or vomiting carefully. Conditions that predispose patients to developing hypoglycemia or hyperglycemia may also alter metformin; rosiglitazone and other antidiabetic agent efficacy. Conditions associated with hypoglycemia include insufficient caloric intake, strenuous exercise, debilitated physical condition, drug interactions (e.g., additional hypoglycemic agents), malnutrition, uncontrolled adrenal insufficiency, pituitary insufficiency or hypothyroidism. Hypoglycemia may be difficult to recognize in geriatric patients and those taking beta-blockers. Hyperglycemia-related conditions include drug interactions, female hormonal changes, elevated temperature, severe psychological stress, and uncontrolled hypercortisolism or hyperthyroidism. More frequent blood glucose monitoring may be necessary in patients with these conditions.

    Anemia, pernicious anemia

    Use metformin; rosiglitazone with caution in patients with pre-existing anemia of any cause or pernicious anemia. Decreases in mean hemoglobin and hematocrit occurred in a dose-related fashion in adult patients treated with rosiglitazone and the observed changes may be related to the increased plasma volume observed with treatment with rosiglitazone. In addition, metformin may result in suboptimal vitamin B12 absorption, possibly due to interference with the B12-intrinsic factor complex. The interaction very rarely results in a pernicious anemia that appears reversible with discontinuation of metformin or with cyanocobalamin supplementation. Certain individuals may be predisposed to this type of anemia; a nested case-control study of 465 patients taking metformin (155 with vitamin B12 deficiency and 310 without) demonstrated that dose and duration of metformin use may be associated with an increased odds of vitamin B12 deficiency. Each 1 gram/day increment in dose significantly increased the odds of vitamin B12 deficiency (OR 2.88, 95% CI 2.15 to 3.87) as did taking metformin for 3 years or more (OR 2.39, 95% CI 1.46 to 3.91). Regular measurement of hematologic parameters is recommended in all patients on chronic metformin treatment.

    Bone fractures, osteoporosis

    Use rosiglitazone; metformin with caution in female patients with osteoporosis or risk factors for osteopenia. Long-term trials (ADOPT and RECORD) show an increased incidence of bone fractures in patients, particularly female patients, taking rosiglitazone. This increased incidence was noted after the first year of treatment and persisted during the course of the trial. The majority of the fractures in the women who received rosiglitazone occurred in the upper arm, hand, and foot. These sites of fracture are different from those usually associated with postmenopausal osteoporosis (e.g., hip or spine). Other trials suggest that this risk may also apply to men, although the risk of fracture among women appears higher than that among men. The risk of fracture should be considered in the care of patients treated with metformin; rosiglitazone and attention given to assessing and maintaining bone health according to current standards of care.

    Contraception requirements, menstrual irregularity, polycystic ovary syndrome

    Premenopausal anovulatory females with insulin resistance, such as those with polycystic ovary syndrome (PCOS), may resume ovulation as a result of metformin; rosiglitazone therapy; patients may be at risk of becoming pregnant if adequate contraception is not used. Contraception requirements are advised; the use of adequate contraception in premenopausal women of childbearing potential should be recommended. If unexpected menstrual irregularity occurs, the benefits of continued metformin; rosiglitazone therapy should be reviewed.

    Pregnancy

    Metformin; rosiglitazone is not recommended for use during pregnancy. There is a lack of data describing the use of rosiglitazone during human pregnancy. Rosiglitazone has been reported to cross the human placenta and be detectable in fetal tissue; use during pregnancy is not recommended due to lack of data. Metformin has been studied as monotherapy during human pregnancy. The American College of Obstetricians and Gynecologists (ACOG) and the American Diabetes Association (ADA) continue to recommend human insulin as the standard of care in women with diabetes mellitus and gestational diabetes mellitus (GDM) requiring medical therapy; insulin does not cross the placenta. Per ACOG, in women who decline insulin therapy or are unable to safely administer insulin, metformin is the preferred second-line choice. Per the ADA, metformin monotherapy may be used to treat GDM as a treatment option; however, no long term safety data are available for any oral agent. Metformin may cause a lower risk of neonatal hypoglycemia and less maternal weight gain than insulin; however, some data suggest that metformin may slightly increase the risk of prematurity. The ADA notes that in some clinical studies, nearly 50% of GDM patients initially treated with metformin have needed the addition of insulin in order to achieve acceptable glucose control.

    Breast-feeding

    Metformin; rosiglitazone should not be administered to a nursing woman. Animal data suggest that rosiglitazone may be excreted in milk, however, it is unknown if rosiglitazone or its metabolites are excreted in human milk. Due to the potential for adverse effects from rosiglitazone in the nursing infant, use during breast-feeding should be avoided. Metformin monotherapy may be considered, if appropriate. Animal data show that metformin is excreted into breast milk and reaches levels similar to those in plasma and small studies indicate that metformin is excreted in human breast milk. However, adverse effects of metformin exposure through breast milk on infant plasma glucose have not been reported in human studies. Furthermore, the use of metformin 2550 mg/day by mothers breast-feeding their infants for 6 months does not affect growth, motor, or social development; the effects beyond 6 months are not known. In all of these studies, the estimated weight-adjusted infant exposure to metformin ranged from 0.11 to 1.08% of the mother's dose. If blood glucose is not controlled on diet and exercise alone, insulin therapy may also be considered, or other oral hypoglycemics may be considered as possible alternatives during breast feeding. Because acarbose has limited systemic absorption, which results in minimal maternal plasma concentrations, clinically significant exposure via breast milk is not expected. Tolbutamide is usually considered compatible with breast-feeding. Glyburide may be a suitable alternative since it was not detected in the breast milk of lactating women who received single and multiple doses of glyburide. If oral hypoglycemics are used during breast feeding, the nursing infant should be monitored for signs of hypoglycemia, such as increased fussiness or somnolence.

    Children

    Use of metformin; rosiglitazone is not recommended in pediatric patients. Based on the results of a clinical study, the FDA concluded that data are insufficient to recommend the use of rosiglitazone in children. In a 24-week, double-blind clinical trial, children and adolescents 10 to 17 years of age with type 2 diabetes mellitus were randomized to 2 mg PO twice daily of rosiglitazone (n = 99) or 500 mg PO twice daily of metformin (n = 101). After at least 8 weeks of therapy, 49% of rosiglitazone-treated and 55% of metformin-treated patients had their dose doubled due to a fasting plasma glucose of greater than 126 mg/dL. For the overall intent-to-treat population at week 24, the mean decrease from baseline in hemoglobin A1C was 0.14% for rosiglitazone-treated patients versus 0.49% for metformin-treated patients. The power in the study was not sufficient to determine if the changes in A1C between the 2 groups were significantly different. In general, patients naive to diabetic treatment experienced a greater reduction in A1C when compared to those who had been previously treated with diabetic treatment; for patients treated with rosiglitazone, a change in A1C of -0.5% for naive patients vs. 0.1% for previously treated patients occurred, and in patients treated with metformin, these numbers were -0.7% for naive patients versus -0.4% for previously treated patients. Patients treated with rosiglitazone gained more weight than patients treated with metformin (2.8 kg for patients treated with rosiglitazone versus 0.2 kg for patients treated with metformin).

    Geriatric

    Geriatric, debilitated, or malnourished patients are particularly susceptible to hypoglycemic effects of antidiabetic agents; monitor blood glucose frequently. Use metformin; rosiglitazone with caution in geriatric patients due to the potential for lactic acidosis from metformin and the risk for heart failure from rosiglitazone. Metformin is substantially excreted by the kidney and the risk of adverse reactions (including lactic acidosis) is greater in patients with reduced renal function. Renal function (i.e., the eGFR) should be assessed more frequently in the elderly. Unless estimated renal function via the eGFR is determined to be normal, do not use metformin in geriatric patients 80 years and older. Also carefully monitor geriatric patients for signs and symptoms of heart failure after drug initiation and any changes in dose. If such signs and symptoms develop, the heart failure should be managed according to current standards of care; metformin; rosiglitazone therapy should be discontinued if deterioration in cardiac status occurs. Rosiglitazone is contraindicated for use in geriatric patients with NYHA Class III or IV heart failure, and it is not recommended for use in patients with symptomatic or acute heart failure. Rosiglitazone and other thiazolidinediones (TZDs) may increase the risk of hospitalized heart failure and all-cause mortality in the elderly. However, one observational study, which also included an analysis in a subpopulation of patients more than 65 years of age, found no statistically significant increase in emergency department visits or hospitalization for heart failure, or all-cause mortality, between patients treated with rosiglitazone vs. pioglitazone, including in the subgroup. One additional small, prospective, observational study found no statistically significant differences for cardiovascular mortality and all-cause mortality in patients treated with rosiglitazone compared to pioglitazone. Some uncertainty remains over the risk of heart failure due to the TZD agents.[28172] [33633] [34781] [43362] According to the Beers Criteria, rosiglitazone is considered a potentially inappropriate medication (PIM) in geriatric patients with heart failure; avoid use due to the potential for fluid retention and exacerbation of the condition.[63923] The federal Omnibus Budget Reconciliation Act (OBRA) regulates medication use in residents of long-term care facilities (LTCFs). According to OBRA, the use of antidiabetic medications should include monitoring (e.g., periodic blood glucose) for effectiveness based on desired goals for that individual and to identify complications of treatment such as hypoglycemia. Rosiglitazone has been associated with edema and weight gain and use should be avoided in those with NYHA Stage III or Stage IV heart failure. Monitor patients receiving rosiglitazone for visual deterioration due to new onset or worsening of macular edema.Metformin has been associated with lactic acidosis, which is more likely to occur under the following conditions: serum creatinine of 1.5 mg/dL or higher in males or 1.4 mg/dL or higher in females, abnormal creatinine clearance from any cause, age of 80 years or older unless measurement of eGFR verifies normal renal function, radiologic studies in which intravascular iodinated contrast materials are given, congestive heart failure requiring pharmacologic management, or acute/chronic metabolic acidosis with or without coma (including diabetic ketoacidosis).

    ADVERSE REACTIONS

    Severe

    bone fractures / Delayed / 9.3-9.3
    myocardial infarction / Delayed / 2.9-2.9
    heart failure / Delayed / 2.7-2.7
    megaloblastic anemia / Delayed / 0-1.0
    lactic acidosis / Delayed / 0-0.1
    pulmonary edema / Early / Incidence not known
    pleural effusion / Delayed / Incidence not known
    hepatic necrosis / Delayed / Incidence not known
    hepatic failure / Delayed / Incidence not known
    hepatic encephalopathy / Delayed / Incidence not known
    visual impairment / Early / Incidence not known
    macular edema / Delayed / Incidence not known
    anaphylactoid reactions / Rapid / Incidence not known
    Stevens-Johnson syndrome / Delayed / Incidence not known
    rhabdomyolysis / Delayed / Incidence not known

    Moderate

    anemia / Delayed / 1.9-7.1
    vitamin B12 deficiency / Delayed / 7.0-7.0
    peripheral edema / Delayed / 4.4-4.4
    hypoglycemia / Early / 3.0-3.0
    hyperbilirubinemia / Delayed / 0.3-0.3
    elevated hepatic enzymes / Delayed / 0.2-0.2
    metabolic acidosis / Delayed / 0-0.1
    folate deficiency / Delayed / Incidence not known
    edema / Delayed / Incidence not known
    angina / Early / Incidence not known
    dyspnea / Early / Incidence not known
    hypercholesterolemia / Delayed / Incidence not known
    cholestasis / Delayed / Incidence not known
    hepatitis / Delayed / Incidence not known
    jaundice / Delayed / Incidence not known
    blurred vision / Early / Incidence not known
    osteopenia / Delayed / Incidence not known

    Mild

    infection / Delayed / 5.0-16.0
    diarrhea / Early / 12.7-12.7
    dyspepsia / Early / 1.0-10.0
    vomiting / Early / 1.0-10.0
    anorexia / Delayed / 1.0-10.0
    dysgeusia / Early / 1.0-10.0
    metallic taste / Early / 1.0-10.0
    flatulence / Early / 1.0-10.0
    abdominal pain / Early / 1.0-10.0
    nausea / Early / 1.0-10.0
    weight gain / Delayed / 6.9-6.9
    headache / Early / 6.5-6.5
    sinusitis / Delayed / 6.2-6.2
    fatigue / Early / 5.9-5.9
    malaise / Early / 1.0-5.0
    myalgia / Early / 1.0-5.0
    flushing / Rapid / 1.0-5.0
    dizziness / Early / 1.0-5.0
    back pain / Delayed / 5.0-5.0
    arthralgia / Delayed / 5.0-5.0
    pharyngitis / Delayed / 3.0-3.0
    menstrual irregularity / Delayed / 0-0.4
    pruritus / Rapid / Incidence not known
    rash / Early / Incidence not known
    urticaria / Rapid / Incidence not known

    DRUG INTERACTIONS

    Abacavir; Dolutegravir; Lamivudine: (Major) If these drugs are used in combination, the total daily dose of metformin must not exceed 1,000 mg/day. Dolutegravir may increase exposure to metformin. Increased exposure to metformin may increase the risk for hypoglycemia, gastrointestinal side effects, and potentially increase the risk for lactic acidosis. Consider the benefits and risks of concomitant use of dolutegravir with metformin. Close monitoring of blood glucose and patient clinical status (gastrointestinal side effects, renal function, electrolytes and acid-base balance) is recommended. When stopping dolutegravir, the metformin dose may need to be adjusted. In drug interaction studies, dolutegravir increased both the Cmax and AUC of metformin when metformin 500 mg PO twice daily was coadministered. Dolutegravir inhibits common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2]/multidrug and toxin extrusion [MATE1 and MATE2k]). (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Abacavir; Lamivudine, 3TC: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Abacavir; Lamivudine, 3TC; Zidovudine, ZDV: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Abiraterone: (Moderate) Monitor blood sugar more frequently if coadministration of rosiglitazone with abiraterone is necessary. Rosiglitazone is a CYP2C8 substrate and abiraterone is a weak CYP2C8 inhibitor. Severe hypoglycemia has been reported when abiraterone was administered to patients receiving thiazolidinediones.
    Acalabrutinib: (Moderate) Consider the benefits and risks of concomitant therapy of acalabrutinib with metformin. Concomitant use o fmedications that interfere with common renal tubular transport systems involved in the renal elimination of metformin (e.g., MATE inhibitors) could increase systemic exposure to metformin and increase the risk for lactic acidosis. The active metabolite of acalabrutinib (ACP-5862) inhibits MATE1 in vitro and may have the potential to increase concentrations of coadministered substrates of these transporters.
    Acebutolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetaminophen; Guaifenesin; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetaminophen; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Acetazolamide: (Moderate) Carbonic anhydrase inhibitors such as acetazolamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of acetazolamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction. (Minor) Carbonic anhydrase inhibitors may alter blood sugar. Both hyperglycemia and hypoglycemia have been described in patients treated with acetazolamide. This should be taken into consideration in patients with impaired glucose tolerance or diabetes mellitus who are receiving antidiabetic agents. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Acetohexamide: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Acrivastine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Adefovir: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion (e.g., adefovir) may decrease metformin elimination by competing for common renal tubular transport systems. Although such interactions remain theoretical, careful patient monitoring and dose adjustment of metformin and/or the interfering cationic drug are recommended.
    Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Aliskiren; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Aliskiren; Valsartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Amiloride; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Amlodipine; Benazepril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Amlodipine; Olmesartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Amlodipine; Valsartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Amlodipine; Valsartan; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Amoxicillin; Clarithromycin; Omeprazole: (Moderate) The concomitant use of clarithromycin and antidiabetic agents can result in significant hypoglycemia. Careful monitoring of blood glucose is recommended. (Moderate) The concomitant use of clarithromycin and oral hypoglycemic agents can result in significant hypoglycemia. With certain hypoglycemic drugs such as the thiazolidinediones, inhibition of CYP3A enzyme by clarithromycin may be involved; however, CYP3A is not a major metabolism route for pioglitazone and rosiglitazone. Careful monitoring of glucose is recommended.
    Amphetamine: (Moderate) Monitor for loss of glycemic control when amphetamines are administered to patients taking antidiabetic agents. Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Sympathomimetic agents, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells.
    Amphetamine; Dextroamphetamine: (Moderate) Monitor for loss of glycemic control when amphetamines are administered to patients taking antidiabetic agents. Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Sympathomimetic agents, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells.
    Amphetamines: (Moderate) Monitor for loss of glycemic control when amphetamines are administered to patients taking antidiabetic agents. Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Sympathomimetic agents, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells.
    Amyl Nitrite: (Major) The concomitant use of nitrates with rosiglitazone is not recommended. An increased risk of myocardial ischemia was observed in a subset of patients receiving nitrates with rosiglitazone. Most patients that were using nitrates had preexisting coronary artery disease. In patients with coronary artery disease that were not on nitrates, rosiglitazone therapy did not increase the risk of myocardial ischemia.
    Androgens: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Angiotensin II receptor antagonists: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Angiotensin-converting enzyme inhibitors: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Aprepitant, Fosaprepitant: (Minor) Use caution if rosiglitazone and aprepitant are used concurrently and monitor for a possible decrease in the efficacy of rosiglitazone. After administration, fosaprepitant is rapidly converted to aprepitant and shares the same drug interactions. Rosiglitazone is an in vitro CYP2C9 substrate and aprepitant is a CYP2C9 inducer. Administration of a CYP2C9 substrate, tolbutamide, on days 1, 4, 8, and 15 with a 3-day regimen of oral aprepitant (125 mg/80 mg/80 mg) decreased the tolbutamide AUC by 23% on day 4, 28% on day 8, and 15% on day 15. The AUC of tolbutamide was decreased by 8% on day 2, 16% on day 4, 15% on day 8, and 10% on day 15 when given prior to oral administration of aprepitant 40 mg on day 1, and on days 2, 4, 8, and 15. The effects of aprepitant on tolbutamide were not considered significant. When a 3-day regimen of aprepitant (125 mg/80 mg/80 mg) given to healthy patients on stabilized chronic warfarin therapy (another CYP2C9 substrate), a 34% decrease in S-warfarin trough concentrations was noted, accompanied by a 14% decrease in the INR at five days after completion of aprepitant.
    Asciminib: (Moderate) Monitor for an increase in rosiglitazone-related adverse effects during concomitant use with asciminib; adjust the dose of rosiglitazone based on clinical response. Coadministration may increase the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 and CYP2C9 substrate and asciminib is a CYP2C8 and CYP2C9 inhibitor. Coadministration of rosiglitazone with asciminib 40 mg twice daily, 80 mg once daily, and 200 mg twice daily increased the exposure of rosiglitazone by 20%, 24% and 66%, respectively.
    Atazanavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Atazanavir; Cobicistat: (Moderate) Concurrent administration of metformin and cobicistat may increase the risk of lactic acidosis. Cobicistat is a potent inhibitor of the human multidrug and toxic extrusion 1 (MATE1) on proximal renal tubular cells; metformin is a MATE1 substrate. Inhibition of MATE1 by cobicistat may decrease metformin eliminiation by blocking renal tubular secretion. If these drugs are given together, closely monitor for signs of metformin toxicity; metformin dose adjustments may be needed. (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Atenolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Atenolol; Chlorthalidone: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    atypical antipsychotic: (Moderate) Atypical antipsychotic therapy may aggravate diabetes mellitus and cause metabolic changes such as hyperglycemia. Monitor patients on antidiabetic agents for worsening glycemic control. Atypical antipsychotics have been associated with metabolic changes, including hyperglycemia, diabetic ketoacidosis, hyperosmolar, hyperglycemic states, and diabetic coma. Aggravation of diabetes mellitus has been reported. Possible mechanisms include atypical antipsychotic-induced insulin resistance or direct beta-cell inhibition. (Moderate) Monitor blood glucose during concomitant atypical antipsychotic and metformin use. Atypical antipsychotic therapy may aggravate diabetes mellitus. Atypical antipsychotics have been associated with metabolic changes, including hyperglycemia, diabetic ketoacidosis, hyperosmolar, hyperglycemic states, and diabetic coma. Possible mechanisms include atypical antipsychotic-induced insulin resistance or direct beta-cell inhibition.
    Avanafil: (Minor) Avanafil is a weak inhibitor of CYP2C8 isoenzymes. A single avanafil (200 mg) dose increased AUC by 2% and decreased Cmax by 14% of a single rosiglitazone (8 mg) dose, a CYP2C8 substrate.
    Azelastine; Fluticasone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Azilsartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Azilsartan; Chlorthalidone: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Beclomethasone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Benazepril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Benazepril; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Bendroflumethiazide; Nadolol: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Benzphetamine: (Moderate) Monitor for loss of glycemic control when amphetamines are administered to patients taking antidiabetic agents. Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Sympathomimetic agents, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells.
    Beta-blockers: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Betamethasone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Betaxolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Bexarotene: (Moderate) Systemic bexarotene may enhance the action of insulin sensitizers (e.g., thiazolidinediones) resulting in hypoglycemia. Patients should be closely monitored while receiving bexarotene capsules in combination with any of these agents; monitor for hypoglycemia and need for diabetic therapy adjustments. Hypoglycemia has not been associated with bexarotene monotherapy.
    Bictegravir; Emtricitabine; Tenofovir Alafenamide: (Moderate) Caution is advised when administering bictegravir with metformin, as coadministration may increase exposure to metformin and increase the risk for hypoglycemia, gastrointestinal side effects, and potentially increase the risk for lactic acidosis. Close monitoring of blood glucose and patient clinical status is recommended. In drug interaction studies, bictegravir increased both the Cmax and AUC of metformin at a metformin dose of 500 mg PO twice daily. Bictegravir inhibits common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2]/multidrug and toxin extrusion [MATE1]).
    Bisoprolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Bisoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Bortezomib: (Moderate) During clinical trials of bortezomib, hypoglycemia and hyperglycemia were reported in diabetic patients receiving antidiabetic agents. Patients taking antidiabetic agents and receiving bortezomib treatment may require close monitoring of their blood glucose levels and dosage adjustment of their medication.
    Brigatinib: (Moderate) Consider the benefits and risks of concomitant therapy of brigatinib with metformin. Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (e.g., MATE inhibitors) could increase systemic exposure to metformin and increase the risk for lactic acidosis. Brigatinib inhibits MATE1 and MATE2K in vitro and may have the potential to increase concentrations of coadministered substrates of these transporters.
    Brimonidine; Timolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Brompheniramine; Carbetapentane; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Brompheniramine; Dextromethorphan; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Brompheniramine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Brompheniramine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Budesonide: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Budesonide; Formoterol: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Budesonide; Glycopyrrolate; Formoterol: (Moderate) Coadministration of glycopyrrolate with metformin my increase metformin plasma concentrations, which may lead to increased metformin effects and possible adverse events. If coadministration is necessary, monitor clinical response to metformin and adjust metformin dose accordingly. (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Bumetanide: (Minor) Bumetanide has been associated with hyperglycemia, possibly due to potassium depletion, and, glycosuria has been reported. Because of this, a potential pharmacodynamic interaction exists between bumetanide and all antidiabetic agents. This interference can lead to a loss of diabetic control, so diabetic patients should be monitored closely.
    Calcium Carbonate; Famotidine; Magnesium Hydroxide: (Minor) Famotidine may decrease the renal clearance of metformin secondary to competition for renal tubular transport systems. Such an interaction has been observed when cimetidine was administered with metformin. The decrease in renal excretion led to a 40% increase in metformin AUC. Although interactions with cationic drugs remain theoretical (except for cimetidine), caution is warranted when famotidine and metformin are prescribed concurrently. Famotidine may be less likely to interact with metformin versus cimetidine or ranitidine because of less tubular excretion.
    Candesartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Candesartan; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Cannabidiol: (Moderate) Consider a dose reduction of rosiglitazone as clinically appropriate, if adverse reactions occur when administered with cannabidiol. Increased rosiglitazone exposure is possible. Rosiglitazone is a CYP2C8 substrate. In vitro data predicts inhibition of CYP2C8 by cannabidiol potentially resulting in clinically significant interactions.
    Capmatinib: (Moderate) Monitor for an increased risk of metformin-related adverse reactions including lactic acidosis if coadministration with capmatinib is necessary; consider the benefits and risks of concomitant use. Metformin is a substrate of multidrug and toxin extrusion (MATE) and capmatinib is a MATE1 and MATE2K inhibitor. Coadministration may interfere with the renal elimination of metformin and increase metformin exposure.
    Captopril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Captopril; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Carbetapentane; Chlorpheniramine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carbetapentane; Diphenhydramine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carbetapentane; Guaifenesin; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carbetapentane; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carbetapentane; Phenylephrine; Pyrilamine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carbetapentane; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carbinoxamine; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carbinoxamine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carbinoxamine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Carteolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Carvedilol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Cenobamate: (Moderate) Monitor for a decrease in rosiglitazone efficacy during concomitant use with cenobamate; adjust the dose of rosiglitazone based on clinical response. Coadministration may decrease the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 substrate and cenobamate is a CYP2C8 inducer.
    Cephalexin: (Moderate) Monitor for metformin-related adverse reactions during concomitant cephalexin use; a metformin dosage adjustment may be necessary. Concomitant use results in increased serum metformin concentrations and decreased renal clearance of metformin. In healthy subjects given single cephalexin 500 mg doses and metformin, serum metformin mean Cmax and AUC increased by an average of 34% and 24%, respectively, and metformin mean renal clearance decreased by 14%.
    Cetirizine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chlophedianol; Guaifenesin; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chloroquine: (Major) Careful monitoring of blood glucose is recommended when chloroquine and antidiabetic agents, including metformin, are coadministered. A decreased dose of the antidiabetic agent may be necessary as severe hypoglycemia has been reported in patients treated concomitantly with chloroquine and an antidiabetic agent. (Major) Careful monitoring of blood glucose is recommended when chloroquine and antidiabetic agents, including the thiazolidinediones, are coadministered. A decreased dose of the antidiabetic agent may be necessary as severe hypoglycemia has been reported in patients treated concomitantly with chloroquine and an antidiabetic agent.
    Chlorothiazide: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chlorpheniramine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chlorpheniramine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Chlorpropamide: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Chlorthalidone: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Chlorthalidone; Clonidine: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Minor) Increased frequency of blood glucose monitoring may be required when clonidine is given with antidiabetic agents. Since clonidine inhibits the release of catecholamines, clonidine may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Clonidine does not appear to impair recovery from hypoglycemia, and has not been found to impair glucose tolerance in diabetic patients.
    Chromium: (Moderate) Chromium dietary supplements may lower blood glucose. As part of the glucose tolerance factor molecule, chromium appears to facilitate the binding of insulin to insulin receptors in tissues and to aid in glucose metabolism. Because blood glucose may be lowered by the use of chromium, patients who are on antidiabetic agents may need dose adjustments. Close monitoring of blood glucose is recommended.
    Ciclesonide: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Cimetidine: (Moderate) Concomitant administration of metformin and cimetidine may increase metformin exposure and increase the risk for lactic acidosis. If these drugs are given together, monitor for signs of metformin toxicity; metformin dose adjustments may be needed. After administration of single doses of cimetidine 400 mg and metformin 850 mg, mean metformin exposure increased by 40%. Metformin is an OCT2 substrate; cimetidine is an OCT2 inhibitor that may decrease metformin elimination by blocking renal tubular secretion.
    Cisapride: (Moderate) Because cisapride can enhance gastric emptying in diabetic patients, blood glucose can be affected, which, in turn, may affect the clinical response to antidiabetic agents. Monitor blood glucose and adjust if cliniically indicated.
    Clarithromycin: (Moderate) The concomitant use of clarithromycin and antidiabetic agents can result in significant hypoglycemia. Careful monitoring of blood glucose is recommended. (Moderate) The concomitant use of clarithromycin and oral hypoglycemic agents can result in significant hypoglycemia. With certain hypoglycemic drugs such as the thiazolidinediones, inhibition of CYP3A enzyme by clarithromycin may be involved; however, CYP3A is not a major metabolism route for pioglitazone and rosiglitazone. Careful monitoring of glucose is recommended.
    Clofarabine: (Moderate) Concomitant use of clofarabine and metformin may result in altered clofarabine levels because both agents are a substrate of OCT1. Therefore, monitor for signs of clofarabine toxicity such as gastrointestinal toxicity (e.g., nausea, vomiting, diarrhea, mucosal inflammation), hematologic toxicity, and skin toxicity (e.g. hand and foot syndrome, rash, pruritus) in patients also receiving OCT1 substrates.
    Clonidine: (Minor) Increased frequency of blood glucose monitoring may be required when clonidine is given with antidiabetic agents. Since clonidine inhibits the release of catecholamines, clonidine may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Clonidine does not appear to impair recovery from hypoglycemia, and has not been found to impair glucose tolerance in diabetic patients.
    Clopidogrel: (Moderate) Monitor for an increase in rosiglitazone-related adverse effects during concomitant use with clopidogrel; adjust the dose of rosiglitazone based on clinical response. Coadministration may increase the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 substrate and clopidogrel is a CYP2C8 inhibitor.
    Cobicistat: (Moderate) Concurrent administration of metformin and cobicistat may increase the risk of lactic acidosis. Cobicistat is a potent inhibitor of the human multidrug and toxic extrusion 1 (MATE1) on proximal renal tubular cells; metformin is a MATE1 substrate. Inhibition of MATE1 by cobicistat may decrease metformin eliminiation by blocking renal tubular secretion. If these drugs are given together, closely monitor for signs of metformin toxicity; metformin dose adjustments may be needed.
    Codeine; Guaifenesin; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Codeine; Phenylephrine; Promethazine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Colesevelam: (Moderate) The clinical response to metformin extended-release (metformin ER) should be monitored in patients receiving concomitant therapy with colesevelam. Be alert for changes in glycemic control, increased metformin side effects, such as gastrointestinal disturbances and a risk for lactic acidosis. Colesevelam increases the Cmax and AUC of metformin ER by approximately 8% and 44%, respectively. The mechanism of the interaction is not known. Colesevelam has no significant effect on the bioavailability of immediate-release metformin.
    Conjugated Estrogens: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Conjugated Estrogens; Bazedoxifene: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Conjugated Estrogens; Medroxyprogesterone: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Corticosteroids: (Moderate) Monitor blood glucose during concomitant corticosteroid and metformin use; a metformin dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells. (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Cortisone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Cyanocobalamin, Vitamin B12: (Minor) Metformin may result in suboptimal oral vitamin B12 absorption by competitively blocking the calcium-dependent binding of the intrinsic factor-vitamin B12 complex to its receptor. Regular measurement of hematologic parameters is recommended in all patients on chronic metformin treatment; abnormalities should be investigated.
    Cyclosporine: (Moderate) Cyclosporine has been reported to cause hyperglycemia; this effect appears to be dose-related and caused by direct beta-cell toxicity. Therefore, a pharmacodynamic interaction is possible with all antidiabetic agents and cyclosporine. Patients should be monitored for worsening glycemic control if therapy with cyclosporine is initiated in patients receiving antidiabetic agents. (Moderate) Patients should be monitored for worsening glycemic control if therapy with cyclosporine is initiated in patients receiving antidiabetic agents. Cyclosporine has been reported to cause hyperglycemia or exacerbate diabetes mellitus; this effect appears to be dose-related and caused by direct beta-cell toxicity. Also, any drug that deteriorates the renal status of the patient is likely to alter metformin concentrations in the body, so renal function should be carefully monitored during the use of cyclosporine and metformin together.
    Dabrafenib: (Major) The concomitant use of dabrafenib and rosiglitazone may lead to decreased rosiglitazone exposure and loss of efficacy. Use of an alternative agent is recommended. If concomitant use is unavoidable, monitor patients for loss of rosiglitazone efficacy. A change in diabetes treatment may be needed based upon clinical response if dabrafenib is started or stopped during treatment with rosiglitazone. In vitro, dabrafenib is an inducer of CYP2C isoenzymes via activation of the pregnane X receptor and constitutive androstane receptor nuclear receptors. Rosiglitazone is a moderately sensitive CYP2C8 substrate. Administration of rifampin 600 mg/day for 6 days with a single 8 mg dose of rosiglitazone decreased the AUC of rosiglitazone by 66% in a drug interaction study.
    Daclatasvir: (Moderate) Closely monitor blood glucose levels if daclatasvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as daclatasvir.
    Danazol: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Darunavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Darunavir; Cobicistat: (Moderate) Concurrent administration of metformin and cobicistat may increase the risk of lactic acidosis. Cobicistat is a potent inhibitor of the human multidrug and toxic extrusion 1 (MATE1) on proximal renal tubular cells; metformin is a MATE1 substrate. Inhibition of MATE1 by cobicistat may decrease metformin eliminiation by blocking renal tubular secretion. If these drugs are given together, closely monitor for signs of metformin toxicity; metformin dose adjustments may be needed. (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Moderate) Concurrent administration of metformin and cobicistat may increase the risk of lactic acidosis. Cobicistat is a potent inhibitor of the human multidrug and toxic extrusion 1 (MATE1) on proximal renal tubular cells; metformin is a MATE1 substrate. Inhibition of MATE1 by cobicistat may decrease metformin eliminiation by blocking renal tubular secretion. If these drugs are given together, closely monitor for signs of metformin toxicity; metformin dose adjustments may be needed. (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir : (Moderate) Closely monitor blood glucose levels if dasabuvir; ombitasvir; paritaprevir; ritonavir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as dasabuvir; ombitasvir; paritaprevir; ritonavir.
    Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Major) While no dosage adjustment of metformin is recommended in patients with normal hepatic or renal function, careful patient monitoring and dose adjustment of metformin and/or the potentially interfering drug is recommended with concurrent use. Monitor for signs of onset of lactic acidosis such as respiratory distress, somnolence, and non-specific abdominal distress or worsening renal function. Do not use metformin with paritaprevir in patients with renal insufficiency or hepatic impairment. Drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Paritaprevir is an inhibitor of the organic anion transporters OATP1B1 and OATP1B3. While initial drug-drug interaction studies of paritaprevir-containing hepatitis treatments have not noted an effect on metformin concentrations, more study is needed. (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Deflazacort: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Desloratadine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Desogestrel; Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Dexamethasone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Dexbrompheniramine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Dextroamphetamine: (Moderate) Monitor for loss of glycemic control when amphetamines are administered to patients taking antidiabetic agents. Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Sympathomimetic agents, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells.
    Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Diazoxide: (Minor) Diazoxide, when administered intravenously or orally, produces a prompt dose-related increase in blood glucose level, due primarily to an inhibition of insulin release from the pancreas, and also to an extrapancreatic effect. The hyperglycemic effect begins within an hour and generally lasts no more than 8 hours in the presence of normal renal function. The hyperglycemic effect of diazoxide is expected to be antagonized by certain antidiabetic agents (e.g., insulin or a sulfonylurea). Blood glucose should be closely monitored.
    Dichlorphenamide: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Dienogest; Estradiol valerate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Diethylstilbestrol, DES: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Digoxin: (Moderate) Metformin may increase digoxin concentrations, but the magnitude is unclear. Measure serum digoxin concentrations before initiating metformin, and periodically after that. Monitor heart rate and other clinical parameters. Adjust digoxin dose as necessary.
    Diphenhydramine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Disopyramide: (Moderate) Disopyramide may enhance the hypoglycemic effects of antidiabetic agents. Patients receiving disopyramide concomitantly with antidiabetic agents should be monitored for changes in glycemic control.
    Dofetilide: (Major) Dofetilide should be co-administered with metformin with caution since both drugs are actively secreted via cationic secretion and could compete for common renal tubular transport systems. This results in a possible increase in plasma concentrations of either drug. Reduced clearance of metformin may increase the risk for lactic acidosis; increased concentrations of dofetilide may increase the risk for side effects including proarrhythmia. Careful patient monitoring and dose adjustment of metformin and dofetilide is recommended.
    Dolutegravir: (Major) If these drugs are used in combination, the total daily dose of metformin must not exceed 1,000 mg/day. Dolutegravir may increase exposure to metformin. Increased exposure to metformin may increase the risk for hypoglycemia, gastrointestinal side effects, and potentially increase the risk for lactic acidosis. Consider the benefits and risks of concomitant use of dolutegravir with metformin. Close monitoring of blood glucose and patient clinical status (gastrointestinal side effects, renal function, electrolytes and acid-base balance) is recommended. When stopping dolutegravir, the metformin dose may need to be adjusted. In drug interaction studies, dolutegravir increased both the Cmax and AUC of metformin when metformin 500 mg PO twice daily was coadministered. Dolutegravir inhibits common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2]/multidrug and toxin extrusion [MATE1 and MATE2k]).
    Dolutegravir; Lamivudine: (Major) If these drugs are used in combination, the total daily dose of metformin must not exceed 1,000 mg/day. Dolutegravir may increase exposure to metformin. Increased exposure to metformin may increase the risk for hypoglycemia, gastrointestinal side effects, and potentially increase the risk for lactic acidosis. Consider the benefits and risks of concomitant use of dolutegravir with metformin. Close monitoring of blood glucose and patient clinical status (gastrointestinal side effects, renal function, electrolytes and acid-base balance) is recommended. When stopping dolutegravir, the metformin dose may need to be adjusted. In drug interaction studies, dolutegravir increased both the Cmax and AUC of metformin when metformin 500 mg PO twice daily was coadministered. Dolutegravir inhibits common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2]/multidrug and toxin extrusion [MATE1 and MATE2k]). (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Dolutegravir; Rilpivirine: (Major) If these drugs are used in combination, the total daily dose of metformin must not exceed 1,000 mg/day. Dolutegravir may increase exposure to metformin. Increased exposure to metformin may increase the risk for hypoglycemia, gastrointestinal side effects, and potentially increase the risk for lactic acidosis. Consider the benefits and risks of concomitant use of dolutegravir with metformin. Close monitoring of blood glucose and patient clinical status (gastrointestinal side effects, renal function, electrolytes and acid-base balance) is recommended. When stopping dolutegravir, the metformin dose may need to be adjusted. In drug interaction studies, dolutegravir increased both the Cmax and AUC of metformin when metformin 500 mg PO twice daily was coadministered. Dolutegravir inhibits common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2]/multidrug and toxin extrusion [MATE1 and MATE2k]).
    Donepezil; Memantine: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Drugs that are eliminated by renal tubular secretion (e.g., memantine) may decrease metformin elimination by competing for common renal tubular transport systems. It should be noted that in a pharmacokinetic study in which memantine and glyburide; metformin (Glucovance) were coadministered, the pharmacokinetics of memantine, metformin, or glyburide were not altered. Regardless, careful patient monitoring is recommended.
    Doravirine; Lamivudine; Tenofovir disoproxil fumarate: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Dorzolamide; Timolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Drospirenone: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance.
    Drospirenone; Estetrol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Drospirenone; Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Drospirenone; Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Drospirenone; Ethinyl Estradiol; Levomefolate: (Minor) Levomefolate and metformin should be used together cautiously. Plasma concentrations of levomefolate may be reduced during treatment of type 2 diabetes with metformin. Monitor patients for decreased efficacy of levomefolate if these agents are used together. (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Elagolix; Estradiol; Norethindrone acetate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Elbasvir; Grazoprevir: (Moderate) Closely monitor blood glucose levels if elbasvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as elbasvir.
    Elvitegravir: (Minor) Plasma concentrations of rosiglitazone may be decreased when administered concurrently with elvitegravir. Patients may experience a decreased hypoglycemic effect when these drugs are coadministered. Elvitegravir is a CYP2C9 inducer, while rosiglitazone is a CYP2C9 substrate.
    Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Concurrent administration of metformin and cobicistat may increase the risk of lactic acidosis. Cobicistat is a potent inhibitor of the human multidrug and toxic extrusion 1 (MATE1) on proximal renal tubular cells; metformin is a MATE1 substrate. Inhibition of MATE1 by cobicistat may decrease metformin eliminiation by blocking renal tubular secretion. If these drugs are given together, closely monitor for signs of metformin toxicity; metformin dose adjustments may be needed. (Minor) Plasma concentrations of rosiglitazone may be decreased when administered concurrently with elvitegravir. Patients may experience a decreased hypoglycemic effect when these drugs are coadministered. Elvitegravir is a CYP2C9 inducer, while rosiglitazone is a CYP2C9 substrate.
    Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Concurrent administration of metformin and cobicistat may increase the risk of lactic acidosis. Cobicistat is a potent inhibitor of the human multidrug and toxic extrusion 1 (MATE1) on proximal renal tubular cells; metformin is a MATE1 substrate. Inhibition of MATE1 by cobicistat may decrease metformin eliminiation by blocking renal tubular secretion. If these drugs are given together, closely monitor for signs of metformin toxicity; metformin dose adjustments may be needed. (Minor) Plasma concentrations of rosiglitazone may be decreased when administered concurrently with elvitegravir. Patients may experience a decreased hypoglycemic effect when these drugs are coadministered. Elvitegravir is a CYP2C9 inducer, while rosiglitazone is a CYP2C9 substrate.
    Enalapril, Enalaprilat: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Enalapril; Felodipine: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Enalapril; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Entecavir: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion (e.g., entecavir) may decrease metformin elimination by competing for common renal tubular transport systems. Although such interactions remain theoretical, careful patient monitoring and dose adjustment of metformin and/or the interfering cationic drug are recommended.
    Ephedrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Ephedrine; Guaifenesin: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Eprosartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Eprosartan; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Erdafitinib: (Moderate) Consider the benefits and risks of concomitant treatment with metformin and erdafitinib. Metformin is a substrate of organic cationic transporter-2 (OCT2). Erdafitinib is an OCT2 inhibitor. Coadministration with OCT2 inhibitors could increase systemic exposure to metformin and increase the risk for lactic acidosis.
    Esmolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Esterified Estrogens: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Esterified Estrogens; Methyltestosterone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together. (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Estradiol Cypionate; Medroxyprogesterone: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Estradiol; Levonorgestrel: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Estradiol; Norethindrone: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Estradiol; Norgestimate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Estradiol; Progesterone: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Estramustine: (Minor) Estramustine is an estrogen-containing medication and may decrease glucose tolerance. Patients receiving antidiabetic agents should monitor their blood glucose levels frequently due to this potential pharmacodynamic interaction. (Minor) Estramustine should be used cautiously in patients receiving metformin. Patients should routinely monitor their blood glucose as indicated. Estramustine may decrease glucose tolerance leading to hyperglycemia.
    Estrogens: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Estropipate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Ethacrynic Acid: (Moderate) Loop diuretics can decrease the hypoglycemic effects of antidiabetic agents by producing an increase in blood glucose concentrations.Patients receiving antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
    Ethanol: (Major) Patients taking metformin should be advised to avoid alcohol use. Blood lactate concentrations and the lactate to pyruvate ratio are increased during excessive (acute or chronic) intake of alcohol with metformin. (Moderate) Patients should be advised to limit alcohol ingestion when treated with a thiazolidinedione. A single administration of a moderate amount of alcohol did not increase the risk of acute hypoglycemia in type 2 diabetes mellitus patients treated with thiazolidinediones in clinical studies. However, alcohol inhibits gluconeogenesis, which can contribute to or increase the risk for hypoglycemia. In some patients, hypoglycemia can be prolonged. If a patient with diabetes ingests alcohol, they should be counselled to to avoid ingestion of alcohol on an empty stomach, which increases risk for low blood sugar. Patients should also be aware of the carbohydrate intake provided by certain types of alcohol in the diet, which can contribute to poor glycemic control. If a patient chooses to ingest alcohol, they should monitor their blood glucose frequently. Many non-prescription drug products may be formulated with alcohol; instruct patients to scrutinize product labels prior to consumption.
    Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Ethinyl Estradiol; Levonorgestrel; Folic Acid; Levomefolate: (Minor) Levomefolate and metformin should be used together cautiously. Plasma concentrations of levomefolate may be reduced during treatment of type 2 diabetes with metformin. Monitor patients for decreased efficacy of levomefolate if these agents are used together. (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Ethinyl Estradiol; Norelgestromin: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Ethinyl Estradiol; Norethindrone Acetate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Ethinyl Estradiol; Norgestrel: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Ethotoin: (Minor) Ethotoin and other hydantoins have the potential to increase blood glucose and thus interact with antidiabetic agents pharmacodynamically. Monitor blood glucose for changes in glycemic control. Dosage adjustments may be necessary in some patients. (Minor) Phenytoin and other hydantoins have the potential to increase blood glucose and thus interact with antidiabetic agents pharmacodynamically. Monitor blood glucose for changes in glycemic control. Dosage adjustments may be necessary in some patients.
    Ethynodiol Diacetate; Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Etonogestrel: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance.
    Etonogestrel; Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Famotidine: (Minor) Famotidine may decrease the renal clearance of metformin secondary to competition for renal tubular transport systems. Such an interaction has been observed when cimetidine was administered with metformin. The decrease in renal excretion led to a 40% increase in metformin AUC. Although interactions with cationic drugs remain theoretical (except for cimetidine), caution is warranted when famotidine and metformin are prescribed concurrently. Famotidine may be less likely to interact with metformin versus cimetidine or ranitidine because of less tubular excretion.
    Fedratinib: (Moderate) Concurrent use of metformin and fedratinib may produce unpredictable effects. Concomitant administration may increase the risk for metformin adverse events (e.g., lactic acidosis) or reduce metformin's efficacy. If these drugs are given together, monitor for metformin toxicity and efficacy; metformin dose adjustments may be needed. Fedratinib inhibits the common renal tubular transport systems involved in the renal elimination of metformin (e.g., OCT2/MATE1 and MATE2). In a drug interaction study, fedratinib was observed to have no clinically meaningful effect on metformin overall exposure; however, the renal clearance of metformin was decreased by 36% and the glucose lowering effect of metformin appeared to be reduced. The baseline adjusted glucose exposure was about 50% higher in response to an oral glucose challenge when these drugs were administered together.
    Fenofibrate: (Moderate) Dose reductions and increased frequency of glucose monitoring may be required when antidiabetic agents are administered with fibric acid derivatives (e.g., clofibrate, fenofibric acid, fenofibrate, gemfibrozil). Fibric acid derivatives may enhance the hypoglycemic effects of antidiabetic agents through increased insulin sensitivity and decreased glucagon secretion. (Moderate) Monitor blood glucose during concomitant metformin and fibric acid derivative use; a metformin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Fenofibric Acid: (Moderate) Dose reductions and increased frequency of glucose monitoring may be required when antidiabetic agents are administered with fibric acid derivatives (e.g., clofibrate, fenofibric acid, fenofibrate, gemfibrozil). Fibric acid derivatives may enhance the hypoglycemic effects of antidiabetic agents through increased insulin sensitivity and decreased glucagon secretion. (Moderate) Monitor blood glucose during concomitant metformin and fibric acid derivative use; a metformin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Fexofenadine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Fibric acid derivatives: (Moderate) Monitor blood glucose during concomitant metformin and fibric acid derivative use; a metformin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Fluconazole: (Moderate) Fluconazole is an inhibitor of CYP3A4 and CYP2C9. Because rosiglitazone is a substrate of CYP2C9, concomitant use with fluconazole may increase plasma concentrations of rosiglitazone. Patients should be monitored for changes in glycemic control if rosiglitazone is coadministered with fluconazole.
    Fludrocortisone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Flunisolide: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Fluoxetine: (Moderate) Monitor blood glucose during concomitant metformin and fluoxetine use; a metformin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and fluoxetine use; a thiazolidinedione dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Fluoxymesterone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Fluticasone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Fluticasone; Salmeterol: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Fluticasone; Umeclidinium; Vilanterol: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Fluticasone; Vilanterol: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Formoterol; Mometasone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Fosamprenavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Fosinopril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Fosinopril; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Fosphenytoin: (Minor) Fosphenytoin and other hydantoins have the potential to increase blood glucose and thus interact with antidiabetic agents pharmacodynamically. Monitor blood glucose for changes in glycemic control. Dosage adjustments may be necessary in some patients. (Minor) Phenytoin and other hydantoins have the potential to increase blood glucose and thus interact with antidiabetic agents pharmacodynamically. Monitor blood glucose for changes in glycemic control. Dosage adjustments may be necessary in some patients.
    Furosemide: (Minor) Furosemide may cause hyperglycemia and glycosuria in patients with diabetes mellitus, probably due to diuretic-induced hypokalemia. (Minor) Furosemide may cause hyperglycemia and glycosuria in patients with diabetes mellitus, probably due to diuretic-induced hypokalemia. Because of this, a potential pharmacodynamic interaction exists between furosemide and all antidiabetic agents. This interference can lead to a loss of diabetic control, so diabetic patients should be monitored closely.
    Garlic, Allium sativum: (Moderate) Patients receiving antidiabetic agents should use dietary supplements of Garlic, Allium sativum with caution. Constituents in garlic might have some antidiabetic activity, and may increase serum insulin levels and increase glycogen storage in the liver. Monitor blood glucose and glycemic control. Patients with diabetes should inform their health care professionals of their intent to ingest garlic dietary supplements. Some patients may require adjustment to their hypoglycemic medications over time. One study stated that additional garlic supplementation (0.05 to 1.5 grams PO per day) contributed to improved blood glucose control in patients with type 2 diabetes mellitus within 1 to 2 weeks, and had positive effects on total cholesterol and high/low density lipoprotein regulation over time. It is unclear if hemoglobin A1C is improved or if improvements are sustained with continued treatment beyond 24 weeks. Other reviews suggest that garlic may provide modest improvements in blood lipids, but few studies demonstrate decreases in blood glucose in diabetic and non-diabetic patients. More controlled trials are needed to discern if garlic has an effect on blood glucose in patients with diabetes. When garlic is used in foods or as a seasoning, or at doses of 50 mg/day or less, it is unlikely that blood glucose levels are affected to any clinically significant degree.
    Gemfibrozil: (Major) Dose reduction of rosiglitazone may be needed if given with gemfibrozil. Gemfibrozil results in increased rosiglitazone exposure and increases the risk for hypoglycemia. Gemfibrozil is a potent inhibitor of CYP2C8 and rosiglitazone is primarily metabolized via CYP2C8. Concomitant administration of gemfibrozil (600 mg twice daily) and rosiglitazone (4 mg once daily) for 7 days increased rosiglitazone AUC by 127%, compared to the administration of rosiglitazone (4 mg once daily) alone. Fibric acid derivatives also enhance the hypoglycemic effects of antidiabetic agents through increased insulin sensitivity and decreased glucagon secretion. (Moderate) Monitor blood glucose during concomitant metformin and fibric acid derivative use; a metformin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Glecaprevir; Pibrentasvir: (Moderate) Closely monitor blood glucose levels if glecaprevir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as glecaprevir. (Moderate) Closely monitor blood glucose levels if pibrentasvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as pibrentasvir.
    Glimepiride: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Glimepiride; Rosiglitazone: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Glipizide: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Glipizide; Metformin: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Glyburide: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Glyburide; Metformin: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Glycopyrrolate: (Moderate) Coadministration of glycopyrrolate with metformin my increase metformin plasma concentrations, which may lead to increased metformin effects and possible adverse events. If coadministration is necessary, monitor clinical response to metformin and adjust metformin dose accordingly.
    Glycopyrrolate; Formoterol: (Moderate) Coadministration of glycopyrrolate with metformin my increase metformin plasma concentrations, which may lead to increased metformin effects and possible adverse events. If coadministration is necessary, monitor clinical response to metformin and adjust metformin dose accordingly.
    Green Tea: (Moderate) Green tea catechins have been shown to decrease serum glucose concentrations in vitro. Patients with diabetes mellitus taking antidiabetic agents should be monitored closely for hypoglycemia if consuming green tea products. (Moderate) Green tea catechins have been shown to decrease serum glucose concentrations in vitro. Patients with diabetes mellitus taking antidiabetic agents should be monitored closely for hypoglycemia if consuming green tea products.
    Guaifenesin; Hydrocodone; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Guaifenesin; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Guaifenesin; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Hydantoins: (Minor) Phenytoin and other hydantoins have the potential to increase blood glucose and thus interact with antidiabetic agents pharmacodynamically. Monitor blood glucose for changes in glycemic control. Dosage adjustments may be necessary in some patients.
    Hydralazine; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Hydralazine; Isosorbide Dinitrate, ISDN: (Major) The concomitant use of nitrates with rosiglitazone is not recommended. An increased risk of myocardial ischemia was observed in a subset of patients receiving nitrates with rosiglitazone. Most patients that were using nitrates had preexisting coronary artery disease. In patients with coronary artery disease that were not on nitrates, rosiglitazone therapy did not increase the risk of myocardial ischemia.
    Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Hydrochlorothiazide, HCTZ; Moexipril: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Hydrocodone; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Hydrocortisone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Hydroxychloroquine: (Moderate) Monitor blood glucose during concomitant metformin and hydroxychloroquine use; a metformin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and hydroxychloroquine use; a thiazolidinedione dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Hydroxyprogesterone: (Minor) Progestins, like hydroxyprogesterone, can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued.
    Ibuprofen; Famotidine: (Minor) Famotidine may decrease the renal clearance of metformin secondary to competition for renal tubular transport systems. Such an interaction has been observed when cimetidine was administered with metformin. The decrease in renal excretion led to a 40% increase in metformin AUC. Although interactions with cationic drugs remain theoretical (except for cimetidine), caution is warranted when famotidine and metformin are prescribed concurrently. Famotidine may be less likely to interact with metformin versus cimetidine or ranitidine because of less tubular excretion.
    Ibuprofen; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Indacaterol; Glycopyrrolate: (Moderate) Coadministration of glycopyrrolate with metformin my increase metformin plasma concentrations, which may lead to increased metformin effects and possible adverse events. If coadministration is necessary, monitor clinical response to metformin and adjust metformin dose accordingly.
    Indapamide: (Moderate) A potential pharmacodynamic interaction exists between indapamide and antidiabetic agents, like metformin. Indapamide can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. (Moderate) A potential pharmacodynamic interaction exists between indapamide and antidiabetic agents, such as thiazolidinediones. Indapamide can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia.
    Indinavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Insulin Aspart: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Aspart; Insulin Aspart Protamine: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Degludec: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Degludec; Liraglutide: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Detemir: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Glargine: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Glargine; Lixisenatide: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Glulisine: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Lispro: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin Lispro; Insulin Lispro Protamine: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulin, Inhaled: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Insulins: (Major) Use of insulins with rosiglitazone is not recommended by the manufacturer due to a potential increased risk for edema or heart failure. If heart failure develops in a patient receiving insulin and a thiazoladinedione, manage the patient according to standards of care, and discontinue or consider reducing the dose of the thiazoladinedione. Since the incidence of hypoglycemia may also be higher with combined therapy, patients should also be instructed to monitor blood glucose concentrations more frequently. In five 26-week trials involving patients with type 2 diabetes, rosiglitazone added to insulin therapy (n=867) was compared with insulin therapy alone (n=663). These trials included patients with chronic diabetes and a high prevalence of coexisting medical conditions, including peripheral neuropathy, retinopathy, ischemic heart disease, vascular disease, and congestive heart failure. In these clinical studies, an increased incidence of heart failure and other cardiovascular adverse events was seen in patients receiving combination rosiglitazone and insulin therapy compared to insulin monotherapy; the incidence of new onset or exacerbated heart failure was 0.9% in patients treated with insulin alone vs. 2% in patients treated with insulin plus rosiglitazone. Some of the patients who developed cardiac failure on combination therapy during the double blind part of the studies had no known prior evidence of congestive heart failure, or pre-existing cardiac condition. Additionally, the results of a meta-analysis that included the same 5 randomized, controlled trials mentioned previously indicate that the rate of myocardial ischemia may be increased in patients taking rosiglitazone in combination with insulin; the incidence of myocardia ischemia was 1.4% in patients receiving insulin monotherapy vs. 2.8% in patients receiving rosiglitazone and insulin combination therapy (OR 2.1 95% CI 0.9-5.1). The cardiovascular events were noted at doses of both 4 mg/day and 8 mg/day of rosiglitazone. In a sixth 26-week study, patients with baseline congestive heart failure were excluded; in this study, compared to insulin monotherapy (n=158), the addition of rosiglitazone to insulin therapy (n=161) did not increase the risk of congestive heart failure. One each of myocardial ischemia and sudden death were reported in patients taking combination therapy compared to zero patients taking insulin monotherapy. When rosiglitazone was added to insulin therapy, the incidence of hypoglycemia was higher with 8 mg/day of rosiglitazone (67%) compared to 4 mg/day (53%). (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Iodipamide Meglumine: (Contraindicated) Metformin and combination products containing metformin should be temporarily discontinued prior to the administration of iodinated contrast media. Metformin should be held for at least 48 hours after contrast administration and not restarted until renal function returns to normal post-procedure. Lactic acidosis has been reported in patients taking metformin that experience nephrotoxicity after use of iodinated contrast media.
    Ionic Contrast Media: (Contraindicated) Metformin and combination products containing metformin should be temporarily discontinued prior to the administration of iodinated contrast media. Metformin should be held for at least 48 hours after contrast administration and not restarted until renal function returns to normal post-procedure. Lactic acidosis has been reported in patients taking metformin that experience nephrotoxicity after use of iodinated contrast media.
    Ioxaglate Meglumine; Ioxaglate Sodium: (Contraindicated) Metformin and combination products containing metformin should be temporarily discontinued prior to the administration of iodinated contrast media. Metformin should be held for at least 48 hours after contrast administration and not restarted until renal function returns to normal post-procedure. Lactic acidosis has been reported in patients taking metformin that experience nephrotoxicity after use of iodinated contrast media.
    Irbesartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Irbesartan; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Isocarboxazid: (Moderate) Monitor blood glucose during concomitant thiazolidinedione and monoamine oxidase inhibitor (MAOI) use; a thiazolidinedione dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Minor) The coadministration of rifampin and rosiglitazone may decrease the concentration of rosiglitazone. This interaction is most likely due to rifampin's inhibition of the CYP2C8 and, to a lesser extent, CYP2C9 isozymes. Use caution if rifampin and rosiglitazone are to be coadministered, as decreased rosiglitazone efficacy may be seen. Blood glucose concentrations should be monitored and possible dose adjustments of rosiglitazone may need to be made.
    Isoniazid, INH; Rifampin: (Minor) The coadministration of rifampin and rosiglitazone may decrease the concentration of rosiglitazone. This interaction is most likely due to rifampin's inhibition of the CYP2C8 and, to a lesser extent, CYP2C9 isozymes. Use caution if rifampin and rosiglitazone are to be coadministered, as decreased rosiglitazone efficacy may be seen. Blood glucose concentrations should be monitored and possible dose adjustments of rosiglitazone may need to be made.
    Isophane Insulin (NPH): (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Isosorbide Dinitrate, ISDN: (Major) The concomitant use of nitrates with rosiglitazone is not recommended. An increased risk of myocardial ischemia was observed in a subset of patients receiving nitrates with rosiglitazone. Most patients that were using nitrates had preexisting coronary artery disease. In patients with coronary artery disease that were not on nitrates, rosiglitazone therapy did not increase the risk of myocardial ischemia.
    Isosorbide Mononitrate: (Major) The concomitant use of nitrates with rosiglitazone is not recommended. An increased risk of myocardial ischemia was observed in a subset of patients receiving nitrates with rosiglitazone. Most patients that were using nitrates had preexisting coronary artery disease. In patients with coronary artery disease that were not on nitrates, rosiglitazone therapy did not increase the risk of myocardial ischemia.
    Ketoconazole: (Moderate) Concomitant administration of metformin and ketoconazole may increase metformin exposure and increase the risk for lactic acidosis. If these drugs are given together, monitor for signs of metformin toxicity; metformin dose adjustments may be needed. Metformin is a human multidrug and toxic extrusion (MATE) and OCT2 substrate and ketoconazole is a MATE and OCT2 inhibitor. MATE and OCT2 inhibitors may decrease metformin elimination by blocking renal tubular secretion. (Moderate) If ketoconazole and rosiglitazone are to be coadministered, patients should be closely monitored. A pharmacokinetic study found that the administration of rosiglitazone to subjects who had been receiving ketoconazole resulted in increased rosiglitazone AUC, peak plasma concentrations, and half-life, and decreased rosiglitazone clearance. The clinical significance (i.e., altered blood glucose concentrations) of this interaction is unknown.
    Labetalol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Lamivudine, 3TC: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Lamivudine, 3TC; Zidovudine, ZDV: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, such as lamivudine, may decrease metformin elimination by competing for common renal tubular transport systems.
    Lamotrigine: (Moderate) Concomitant administration of metformin and lamotrigine may increase metformin exposure and increase the risk for lactic acidosis. If these drugs are given together, monitor for signs of metformin toxicity; metformin dose adjustments may be needed. Metformin is an OCT2 substrate; lamotrigine is an OCT2 inhibitor that may decrease metformin elimination by blocking renal tubular secretion.
    Lanreotide: (Moderate) Monitor blood glucose levels regularly in patients with diabetes, especially when lanreotide treatment is initiated or when the dose is altered. Adjust treatment with antidiabetic agents as clinically indicated. Lanreotide inhibits the secretion of insulin and glucagon. Patients treated with lanreotide may experience either hypoglycemia or hyperglycemia.
    Lansoprazole; Amoxicillin; Clarithromycin: (Moderate) The concomitant use of clarithromycin and antidiabetic agents can result in significant hypoglycemia. Careful monitoring of blood glucose is recommended. (Moderate) The concomitant use of clarithromycin and oral hypoglycemic agents can result in significant hypoglycemia. With certain hypoglycemic drugs such as the thiazolidinediones, inhibition of CYP3A enzyme by clarithromycin may be involved; however, CYP3A is not a major metabolism route for pioglitazone and rosiglitazone. Careful monitoring of glucose is recommended.
    Lapatinib: (Moderate) Monitor blood sugar more frequently if coadministration of rosiglitazone with lapatinib is necessary. Rosiglitazone is a CYP2C8 substrate and lapatinib is a weak CYP2C8 inhibitor. Coadministration may increase exposure to rosiglitazone resulting in hypoglycemia.
    Ledipasvir; Sofosbuvir: (Moderate) Closely monitor blood glucose levels if ledipasvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agent(s) may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as ledipasvir. (Moderate) Closely monitor blood glucose levels if sofosbuvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as sofosbuvir.
    Leflunomide: (Moderate) Closely monitor for hypoglycemia and for rosiglitazone-induced side effects when these drugs are used together. In some patients, a dosage reduction of rosiglitazone may be required. Following oral administration, leflunomide is metabolized to an active metabolite, teriflunomide, which is responsible for essentially all of leflunomide's in vivo activity. Rosiglitazone is a substrate for CYP2C8. In vivo data suggest that teriflunomide is an inhibitor of CYP2C8, as Cmax and AUC increased 1.7- and 4.2-fold, respectively, following concurrent use of another CYP2C8 substrate.
    Lente Insulin: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Letermovir: (Moderate) Frequently monitor blood glucose concentrations when rosiglitazone is given with letermovir. Concurrent administration of letermovir, a CYP2C8 inhibitor, with rosiglitazone, a CYP2C8 substrate, may result in a clinically relevant increase in rosiglitazone plasma concentration.
    Leuprolide; Norethindrone: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance.
    Levobetaxolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Levobunolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Levoketoconazole: (Moderate) Concomitant administration of metformin and ketoconazole may increase metformin exposure and increase the risk for lactic acidosis. If these drugs are given together, monitor for signs of metformin toxicity; metformin dose adjustments may be needed. Metformin is a human multidrug and toxic extrusion (MATE) and OCT2 substrate and ketoconazole is a MATE and OCT2 inhibitor. MATE and OCT2 inhibitors may decrease metformin elimination by blocking renal tubular secretion. (Moderate) If ketoconazole and rosiglitazone are to be coadministered, patients should be closely monitored. A pharmacokinetic study found that the administration of rosiglitazone to subjects who had been receiving ketoconazole resulted in increased rosiglitazone AUC, peak plasma concentrations, and half-life, and decreased rosiglitazone clearance. The clinical significance (i.e., altered blood glucose concentrations) of this interaction is unknown.
    Levomefolate: (Minor) Levomefolate and metformin should be used together cautiously. Plasma concentrations of levomefolate may be reduced during treatment of type 2 diabetes with metformin. Monitor patients for decreased efficacy of levomefolate if these agents are used together.
    Levonorgestrel: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance.
    Levonorgestrel; Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Levothyroxine: (Minor) Thyroid hormone use may result in increased blood sugar and a loss of glycemic control in some patients. Interactions may or may not be clinically significant at usual replacement doses. Monitor blood sugars carefully when thyroid therapy is added, changed, or discontinued in patients receiving metformin.
    Levothyroxine; Liothyronine (Porcine): (Minor) Thyroid hormone use may result in increased blood sugar and a loss of glycemic control in some patients. Interactions may or may not be clinically significant at usual replacement doses. Monitor blood sugars carefully when thyroid therapy is added, changed, or discontinued in patients receiving metformin.
    Levothyroxine; Liothyronine (Synthetic): (Minor) Thyroid hormone use may result in increased blood sugar and a loss of glycemic control in some patients. Interactions may or may not be clinically significant at usual replacement doses. Monitor blood sugars carefully when thyroid therapy is added, changed, or discontinued in patients receiving metformin.
    Linezolid: (Moderate) Hypoglycemia, including symptomatic episodes, has been noted in post-marketing reports with linezolid in patients with diabetes mellitus receiving therapy with antidiabetic agents, such as insulin and oral hypoglycemic agents. Diabetic patients should be monitored for potential hypoglycemic reactions while on linezolid. If hypoglycemia occurs, discontinue or decrease the dose of the antidiabetic agent or discontinue the linezolid therapy. Linezolid is a reversible, nonselective MAO inhibitor and other MAO inhibitors have been associated with hypoglycemic episodes in diabetic patients receiving insulin or oral hypoglycemic agents.
    Liothyronine: (Minor) Thyroid hormone use may result in increased blood sugar and a loss of glycemic control in some patients. Interactions may or may not be clinically significant at usual replacement doses. Monitor blood sugars carefully when thyroid therapy is added, changed, or discontinued in patients receiving metformin.
    Lisdexamfetamine: (Moderate) Monitor for loss of glycemic control when amphetamines are administered to patients taking antidiabetic agents. Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Sympathomimetic agents, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells.
    Lisinopril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Lisinopril; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Lonapegsomatropin: (Moderate) Patients with diabetes mellitus should be monitored closely during somatropin (recombinant rhGH) therapy. Antidiabetic drugs (e.g., insulin or oral agents) may require adjustment when somatropin therapy is instituted in these patients. Growth hormones, such as somatropin, may decrease insulin sensitivity, leading to glucose intolerance and loss of blood glucose control. Therefore, glucose levels should be monitored periodically in all patients treated with somatropin, especially in those with risk factors for diabetes mellitus.
    Lopinavir; Ritonavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Loratadine; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Lorcaserin: (Moderate) In general, weight reduction may increase the risk of hypoglycemia in patients with type 2 diabetes mellitus treated with antidiabetic agents, such as insulin and/or insulin secretagogues (e.g., sulfonylureas). In clinical trials, lorcaserin use was associated with reports of hypoglycemia. Blood glucose monitoring is warranted in patients with type 2 diabetes prior to starting and during lorcaserin treatment. Dosage adjustments of anti-diabetic medications should be considered. If a patient develops hypoglycemia during treatment, adjust anti-diabetic drug regimen accordingly. Of note, lorcaserin has not been studied in combination with insulin.
    Losartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Losartan; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Lovastatin; Niacin: (Moderate) Niacin (nicotinic acid) interferes with glucose metabolism and can result in hyperglycemia. Changes in glycemic control can usually be corrected through modification of hypoglycemic therapy. Monitor patients taking antidiabetic agents for changes in glycemic control if niacin (nicotinic acid) is added or deleted to the medication regimen. Dosage adjustments may be necessary. (Moderate) Niacin interferes with glucose metabolism and can result in hyperglycemia. Changes in glycemic control can usually be corrected through modification of hypoglycemic therapy. Monitor patients taking antidiabetic agents for changes in glycemic control if niacin is added or deleted to the medication regimen. Dosage adjustments may be necessary.
    Lumacaftor; Ivacaftor: (Moderate) Although the clinical significance of this interaction is unknown, concurrent use of rosiglitazone and lumacaftor; ivacaftor may alter the therapeutic effects of rosiglitazone; caution and close monitoring of blood glucose are advised if these drugs are administered together. Rosiglitazone is a substrate of CYP2C8 and CYP2C9. In vitro data suggest that lumacaftor; ivacaftor may induce and/or inhibit CYP2C8 and CYP2C9. The net effect on these substrates is not clear, but their exposure may be affected leading to decreased efficacy or increased or prolonged therapeutic effects and adverse events.
    Lumacaftor; Ivacaftor: (Moderate) Although the clinical significance of this interaction is unknown, concurrent use of rosiglitazone and lumacaftor; ivacaftor may alter the therapeutic effects of rosiglitazone; caution and close monitoring of blood glucose are advised if these drugs are administered together. Rosiglitazone is a substrate of CYP2C8 and CYP2C9. In vitro data suggest that lumacaftor; ivacaftor may induce and/or inhibit CYP2C8 and CYP2C9. The net effect on these substrates is not clear, but their exposure may be affected leading to decreased efficacy or increased or prolonged therapeutic effects and adverse events.
    Mafenide: (Moderate) Monitor blood glucose during concomitant metformin and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Mecasermin rinfabate: (Moderate) Use caution in combining mecasermin, recombinant, rh-IGF-1 or mecasermin rinfabate (rh-IGF-1/rh-IGFBP-3) with antidiabetic agents. Patients should be advised to eat within 20 minutes of mecasermin administration. Glucose monitoring is important when initializing or adjusting mecasermin therapies, when adjusting concomitant antidiabetic therapy, and in the event of hypoglycemic symptoms. An increased risk for hypoglycemia is possible. The hypoglycemic effect induced by IGF-1 activity may be exacerbated. The amino acid sequence of mecasermin (rh-IGF-1) is approximately 50 percent homologous to insulin and cross binding with either receptor is possible. Treatment with mecasermin has been shown to improve insulin sensitivity and to improve glycemic control in patients with either Type 1 or Type 2 diabetes mellitus when used alone or in conjunction with insulins.
    Mecasermin, Recombinant, rh-IGF-1: (Moderate) Use caution in combining mecasermin, recombinant, rh-IGF-1 or mecasermin rinfabate (rh-IGF-1/rh-IGFBP-3) with antidiabetic agents. Patients should be advised to eat within 20 minutes of mecasermin administration. Glucose monitoring is important when initializing or adjusting mecasermin therapies, when adjusting concomitant antidiabetic therapy, and in the event of hypoglycemic symptoms. An increased risk for hypoglycemia is possible. The hypoglycemic effect induced by IGF-1 activity may be exacerbated. The amino acid sequence of mecasermin (rh-IGF-1) is approximately 50 percent homologous to insulin and cross binding with either receptor is possible. Treatment with mecasermin has been shown to improve insulin sensitivity and to improve glycemic control in patients with either Type 1 or Type 2 diabetes mellitus when used alone or in conjunction with insulins.
    Medroxyprogesterone: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance.
    Meglitinides: (Moderate) Use of metformin with a meglitinide ("glinide") may increase the risk of hypoglycemia. Meglitinides are insulin secretagogues and are known to cause hypoglycemia. To manage hypoglycemic risk, lower doses of the meglitinide may be needed. Monitor blood sugar.
    Memantine: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Drugs that are eliminated by renal tubular secretion (e.g., memantine) may decrease metformin elimination by competing for common renal tubular transport systems. It should be noted that in a pharmacokinetic study in which memantine and glyburide; metformin (Glucovance) were coadministered, the pharmacokinetics of memantine, metformin, or glyburide were not altered. Regardless, careful patient monitoring is recommended.
    Mestranol; Norethindrone: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Metformin; Repaglinide: (Moderate) Use of metformin with a meglitinide ("glinide") may increase the risk of hypoglycemia. Meglitinides are insulin secretagogues and are known to cause hypoglycemia. To manage hypoglycemic risk, lower doses of the meglitinide may be needed. Monitor blood sugar.
    Methamphetamine: (Moderate) Monitor for loss of glycemic control when amphetamines are administered to patients taking antidiabetic agents. Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Sympathomimetic agents, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells.
    Methazolamide: (Moderate) Carbonic anhydrase inhibitors such as methazolamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of methazolamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction. (Minor) Carbonic anhydrase inhibitors may alter blood sugar. Both hyperglycemia and hypoglycemia have been described in patients treated with acetazolamide. This should be taken into consideration in patients with impaired glucose tolerance or diabetes mellitus who are receiving antidiabetic agents. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Methyclothiazide: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Methylprednisolone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Methyltestosterone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Metolazone: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients.
    Metoprolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Metoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Metyrapone: (Moderate) In patients taking insulin or other antidiabetic agents, the signs and symptoms of acute metyrapone toxicity (e.g., symptoms of acute adrenal insufficiency) may be aggravated or modified.
    Midodrine: (Moderate) Certain medications used concomitantly with metformin may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion, like midodrine, may decrease metformin elimination by competing for common renal tubular transport systems. Careful patient monitoring and dose adjustment of metformin and/or midodrine is recommended.
    Moexipril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Mometasone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Monoamine oxidase inhibitors: (Moderate) Monitor blood glucose during concomitant metformin and monoamine oxidase inhibitor (MAOI) use; a metformin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and monoamine oxidase inhibitor (MAOI) use; a thiazolidinedione dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Nadolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Nandrolone Decanoate: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Naproxen; Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Nateglinide: (Moderate) Use of metformin with a meglitinide ("glinide") may increase the risk of hypoglycemia. Meglitinides are insulin secretagogues and are known to cause hypoglycemia. To manage hypoglycemic risk, lower doses of the meglitinide may be needed. Monitor blood sugar.
    Nebivolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Nebivolol; Valsartan: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Nelfinavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Niacin, Niacinamide: (Moderate) Niacin (nicotinic acid) interferes with glucose metabolism and can result in hyperglycemia. Changes in glycemic control can usually be corrected through modification of hypoglycemic therapy. Monitor patients taking antidiabetic agents for changes in glycemic control if niacin (nicotinic acid) is added or deleted to the medication regimen. Dosage adjustments may be necessary. (Moderate) Niacin interferes with glucose metabolism and can result in hyperglycemia. Changes in glycemic control can usually be corrected through modification of hypoglycemic therapy. Monitor patients taking antidiabetic agents for changes in glycemic control if niacin is added or deleted to the medication regimen. Dosage adjustments may be necessary.
    Niacin; Simvastatin: (Moderate) Niacin (nicotinic acid) interferes with glucose metabolism and can result in hyperglycemia. Changes in glycemic control can usually be corrected through modification of hypoglycemic therapy. Monitor patients taking antidiabetic agents for changes in glycemic control if niacin (nicotinic acid) is added or deleted to the medication regimen. Dosage adjustments may be necessary. (Moderate) Niacin interferes with glucose metabolism and can result in hyperglycemia. Changes in glycemic control can usually be corrected through modification of hypoglycemic therapy. Monitor patients taking antidiabetic agents for changes in glycemic control if niacin is added or deleted to the medication regimen. Dosage adjustments may be necessary.
    Nicardipine: (Moderate) Monitor for an increase in rosiglitazone-related adverse effects during concomitant use with nicardipine; adjust the dose of rosiglitazone based on clinical response. Coadministration may increase the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 substrate and nicardipine is a weak CYP2C8 inhibitor.
    Nicotine: (Minor) Blood glucose concentrations should be monitored more closely whenever a change in either nicotine intake or smoking status occurs; dosage adjustments of metformin may be needed. Nicotine may increase plasma glucose; tobacco smoking is known to aggravate insulin resistance. The cessation of nicotine therapy or tobacco smoking may result in a decrease in blood glucose. (Minor) Nicotine may increase plasma glucose. Blood glucose concentrations should be monitored more closely whenever a change in either nicotine intake or smoking status occurs; dosage adjustments in antidiabetic agents may be needed.
    Nifedipine: (Minor) Nifedipine may increase the plasma metformin Cmax and AUC and increase the amount of metformin excreted in the urine. Metformin half-life is unaffected. Nifedipine appears to enhance the absorption of metformin.
    Nirmatrelvir; Ritonavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Nitrates: (Major) The concomitant use of nitrates with rosiglitazone is not recommended. An increased risk of myocardial ischemia was observed in a subset of patients receiving nitrates with rosiglitazone. Most patients that were using nitrates had preexisting coronary artery disease. In patients with coronary artery disease that were not on nitrates, rosiglitazone therapy did not increase the risk of myocardial ischemia.
    Nitroglycerin: (Major) The concomitant use of nitrates with rosiglitazone is not recommended. An increased risk of myocardial ischemia was observed in a subset of patients receiving nitrates with rosiglitazone. Most patients that were using nitrates had preexisting coronary artery disease. In patients with coronary artery disease that were not on nitrates, rosiglitazone therapy did not increase the risk of myocardial ischemia.
    Non-Ionic Contrast Media: (Major) Discontinue metformin at the time of, or before, administration of non-ionic contrast media to patients with an eGFR of 30 to 60 mL/minute/1.73 m2, history of liver disease, alcoholism, or heart failure, or who will be administered intra-arterial iodinated contrast. Reevaluate eGFR 48 hours after the imaging procedure; restart metformin if renal function is stable. Iodinated contrast agents appear to increase the risk of metformin-induced lactic acidosis, possibly as a result of worsening renal function.
    Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Norethindrone: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance.
    Norethindrone; Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Norgestimate; Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Norgestrel: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance.
    Octreotide: (Moderate) Monitor patients receiving octreotide concomitantly with insulin or other antidiabetic agents for changes in glycemic control and adjust doses of these medications accordingly. Octreotide alters the balance between the counter-regulatory hormones of insulin, glucagon, and growth hormone, which may result in hypoglycemia or hyperglycemia. The hypoglycemia or hyperglycemia which occurs during octreotide acetate therapy is usually mild but may result in overt diabetes mellitus or necessitate dose changes in insulin or other hypoglycemic agents. In patients with concomitant type1 diabetes mellitus, octreotide is likely to affect glucose regulation, and insulin requirements may be reduced. Symptomatic hypoglycemia, which may be severe, has been reported in type 1 diabetic patients. In Type 2 diabetes patients with partially intact insulin reserves, octreotide administration may result in decreases in plasma insulin levels and hyperglycemia.
    Olanzapine; Fluoxetine: (Moderate) Monitor blood glucose during concomitant metformin and fluoxetine use; a metformin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and fluoxetine use; a thiazolidinedione dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Olmesartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Olmesartan; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Olmesartan; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Olopatadine; Mometasone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Ombitasvir; Paritaprevir; Ritonavir: (Major) While no dosage adjustment of metformin is recommended in patients with normal hepatic or renal function, careful patient monitoring and dose adjustment of metformin and/or the potentially interfering drug is recommended with concurrent use. Monitor for signs of onset of lactic acidosis such as respiratory distress, somnolence, and non-specific abdominal distress or worsening renal function. Do not use metformin with paritaprevir in patients with renal insufficiency or hepatic impairment. Drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Paritaprevir is an inhibitor of the organic anion transporters OATP1B1 and OATP1B3. While initial drug-drug interaction studies of paritaprevir-containing hepatitis treatments have not noted an effect on metformin concentrations, more study is needed. (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Oritavancin: (Moderate) Rosiglitazone is metabolized by CYP2C9; oritavancin is a weak CYP2C9 inhibitor. Coadministration may result in elevated rosiglitazone plasma concentrations. If these drugs are administered concurrently, blood glucose should be monitored closely.
    Orlistat: (Minor) Weight-loss may affect glycemic control in patients with diabetes mellitus. In many patients, glycemic control may improve. A reduction in dose of oral hypoglycemic medications may be required in some patients taking orlistat. Monitor blood glucose and glycemic control and adjust therapy as clinically indicated.
    Oxandrolone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Oxymetholone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Pasireotide: (Moderate) Monitor blood glucose levels regularly in patients with diabetes, especially when pasireotide treatment is initiated or when the dose is altered. Adjust treatment with antidiabetic agents as clinically indicated. Pasireotide inhibits the secretion of insulin and glucagon. Patients treated with pasireotide may experience either hypoglycemia or hyperglycemia.
    Pazopanib: (Moderate) Pazopanib is a weak inhibitor of CYP2C8. Coadministration of pazopanib and rosiglitazone, a CYP2C8 substrate, may cause an increase in systemic concentrations of rosiglitazone. Use caution when administering these drugs concomitantly.
    Pegvisomant: (Moderate) Monitor blood glucose levels regularly in patients with diabetes, especially when pegvisomant treatment is initiated or when the dose is altered. Adjust treatment with antidiabetic agents as clinically indicated. Pegvisomant increases sensitivity to insulin by lowering the activity of growth hormone, and in some patients glucose tolerance improves with treatment. Patients with diabetes treated with pegvisomant and antidiabetic agents may be more likely to experience hypoglycemia.
    Penbutolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Pentamidine: (Moderate) Pentamidine can be harmful to pancreatic cells. This effect may lead to hypoglycemia acutely, followed by hyperglycemia with prolonged pentamidine therapy. Patients on antidiabetic agents should be monitored for the need for dosage adjustments during the use of pentamidine.
    Pentoxifylline: (Moderate) Pentoxiphylline has been used concurrently with antidiabetic agents without observed problems, but it may enhance the hypoglycemic action of antidiabetic agents. Patients should be monitored for changes in glycemic control while receiving pentoxifylline in combination with antidiabetic agents.
    Perindopril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Perindopril; Amlodipine: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Phenelzine: (Moderate) Monitor blood glucose during concomitant thiazolidinedione and monoamine oxidase inhibitor (MAOI) use; a thiazolidinedione dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Phenothiazines: (Minor) Phenothiazines, especially chlorpromazine, may increase blood glucose concentrations. Hyperglycemia and glycosuria have been reported. Patients who are taking antidiabetic agents should monitor for worsening glycemic control when a phenothiazine is instituted. (Minor) Phenothiazines, especially chlorpromazine, may increase blood glucose concentrations. Hyperglycemia and glycosuria have been reported. When such drugs are administered to a patient receiving metformin, observe the patient closely for loss of blood glucose control. When such drugs are withdrawn from a patient receiving metformin, observe the patient closely for hypoglycemia.
    Phentermine; Topiramate: (Moderate) Consider more frequent monitoring of patients receiving metformin and concomitant topiramate due to increased risk for lactic acidosis. Carbonic anhydrase inhibitors, such as topiramate, frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. In healthy volunteers, metformin Cmax and AUC increased by 17% and 25%, respectively, when topiramate was added, and oral plasma clearance of topiramate appears to be reduced when administered with metformin. The clinical significance of the effect on the pharmacokinetics of metformin or topiramate are not known.
    Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Phenytoin: (Minor) Phenytoin and other hydantoins have the potential to increase blood glucose and thus interact with antidiabetic agents pharmacodynamically. Monitor blood glucose for changes in glycemic control. Dosage adjustments may be necessary in some patients. (Minor) Phenytoin and other hydantoins have the potential to increase blood glucose and thus interact with antidiabetic agents pharmacodynamically. Monitor blood glucose for changes in glycemic control. Dosage adjustments may be necessary in some patients.
    Pindolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Pioglitazone; Glimepiride: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Prasterone, Dehydroepiandrosterone, DHEA (Dietary Supplements): (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Prasterone, Dehydroepiandrosterone, DHEA (FDA-approved): (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Prednisolone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Prednisone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Pregabalin: (Moderate) Higher rates of peripheral edema and weight gain may occur in patients who concomitantly use thiazolidinediones with pregabalin. As the thiazolidinediones and pregabalin can both cause weight gain and/or fluid retention, possibly exacerbating or leading to heart failure, care should be taken when co-administering these agents.
    Progesterone: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance.
    Progestins: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued.
    Promethazine; Phenylephrine: (Moderate) Sympathomimetic agents and adrenergic agonists tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine, phenylephrine, and other sympathomimetics are administered to patients taking antidiabetic agents. Epinephrine and other sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Propantheline: (Moderate) Propantheline slows GI motility, which may increase the absorption of metformin from the small intestine. A 19% increase in metformin AUC has been reported in studies of this interaction in healthy volunteers. However, no serious side effects resulted.
    Propranolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Propranolol; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Protease inhibitors: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Another possible mechanism is impairment of beta-cell function. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients taking antidiabetic therapy should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Pseudoephedrine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Pseudoephedrine; Triprolidine: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when pseudoephedrine is administered to patients taking metformin. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Pyrimethamine; Sulfadoxine: (Moderate) Monitor blood glucose during concomitant metformin and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Quinapril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Quinapril; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Quinolones: (Moderate) Monitor blood glucose carefully when systemic quinolones and antidiabetic agents, including metformin, are coadministered. Discontinue the quinolone if a hypoglycemic reaction occurs and initiate appropriate therapy immediately. Disturbances of blood glucose, including hyperglycemia and hypoglycemia, have been reported in patients treated concomitantly with quinolones and an antidiabetic agent. Hypoglycemia, sometimes resulting in coma, can occur. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and quinolone use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Ramipril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Ranolazine: (Major) Limit the dose of metformin to 1,700 mg/day in adults if coadministered with ranolazine 1,000 mg twice daily. Coadministration of metformin with ranolazine 1,000 mg twice daily results in increased exposure to metformin. There is potential for an increased risk for lactic acidosis, which is associated with high metformin concentrations. Doses of metformin do not require reduction if coadministered with ranolazine 500 mg twice daily, as metformin exposure was not significantly increased with this lower dose of ranolazine. Ranolazine inhibits common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2]/multidrug and toxin extrusion [MATE1 and MATE2k]). Consider the benefits and risks of concomitant use of ranolazine with metformin. Monitor blood sugar and for gastrointestinal side effects, and increase monitoring for a risk for lactic acidosis, including renal function and electrolytes/acid-base balance.
    Regular Insulin: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Regular Insulin; Isophane Insulin (NPH): (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Relugolix; Estradiol; Norethindrone acetate: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Repaglinide: (Moderate) Use of metformin with a meglitinide ("glinide") may increase the risk of hypoglycemia. Meglitinides are insulin secretagogues and are known to cause hypoglycemia. To manage hypoglycemic risk, lower doses of the meglitinide may be needed. Monitor blood sugar.
    Reserpine: (Moderate) Reserpine may mask the signs and symptoms of hypoglycemia. Patients receiving these drugs concomitantly should be monitored for changes in glycemic control. (Moderate) Reserpine may mask the signs and symptoms of hypoglycemia. Patients receiving these drugs concomitantly with antidiabetic agents should be monitored for changes in glycemic control.
    Rifampin: (Minor) The coadministration of rifampin and rosiglitazone may decrease the concentration of rosiglitazone. This interaction is most likely due to rifampin's inhibition of the CYP2C8 and, to a lesser extent, CYP2C9 isozymes. Use caution if rifampin and rosiglitazone are to be coadministered, as decreased rosiglitazone efficacy may be seen. Blood glucose concentrations should be monitored and possible dose adjustments of rosiglitazone may need to be made.
    Rifapentine: (Moderate) Monitor for a decrease in rosiglitazone efficacy during concomitant use with rifapentine; adjust the dose of rosiglitazone based on clinical response. Coadministration may decrease the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 substrate and rifapentine is a moderate CYP2C8 inducer.
    Risdiplam: (Moderate) Concomitant administration of metformin and risdiplam may increase metformin exposure and increase the risk for lactic acidosis. If these drugs are given together, monitor for signs of metformin toxicity; metformin dose adjustments may be needed. Metformin is a human multidrug and toxic extrusion 1 (MATE1) substrate and risdiplam is a an MATE1/2-K inhibitor. MATE inhibitors may decrease metformin elimination by blocking renal tubular secretion.
    Ritonavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Sacubitril; Valsartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Salicylates: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Saquinavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Segesterone Acetate; Ethinyl Estradiol: (Minor) Monitor blood glucose periodically in patients on metformin for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis. (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. (Minor) Patients receiving antidiabetic agents should be periodically monitored for changes in glycemic control when hormone therapy is instituted or discontinued. Estrogens can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day in combined oral contraceptives (COCs), which are not commonly used in practice since the marketing of lower dose COCs, patches, injections and rings. The presence or absence of a concomitant progestin may influence the significance of any hormonal effect on glucose homeostasis.
    Selpercatinib: (Moderate) Monitor for rosiglitazone-related toxicity if coadministration of rosiglitazone with selpercatinib is necessary. Coadministration may increase exposure to rosiglitazone resulting in increased side effects. Rosiglitazone is a CYP2C8 substrate and selpercatinib is a moderate CYP2C8 inhibitor.
    Sofosbuvir: (Moderate) Closely monitor blood glucose levels if sofosbuvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as sofosbuvir.
    Sofosbuvir; Velpatasvir: (Moderate) Closely monitor blood glucose levels if sofosbuvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as sofosbuvir. (Moderate) Closely monitor blood glucose levels if velpatasvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as velpatasvir.
    Sofosbuvir; Velpatasvir; Voxilaprevir: (Moderate) Closely monitor blood glucose levels if sofosbuvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as sofosbuvir. (Moderate) Closely monitor blood glucose levels if velpatasvir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as velpatasvir. (Moderate) Closely monitor blood glucose levels if voxilaprevir is administered with antidiabetic agents. Dose adjustments of the antidiabetic agents may be needed. Altered blood glucose control, resulting in serious symptomatic hypoglycemia, has been reported in diabetic patients receiving antidiabetic agents in combination with direct acting antivirals, such as voxilaprevir.
    Somatropin, rh-GH: (Moderate) Patients with diabetes mellitus should be monitored closely during somatropin (recombinant rhGH) therapy. Antidiabetic drugs (e.g., insulin or oral agents) may require adjustment when somatropin therapy is instituted in these patients. Growth hormones, such as somatropin, may decrease insulin sensitivity, leading to glucose intolerance and loss of blood glucose control. Therefore, glucose levels should be monitored periodically in all patients treated with somatropin, especially in those with risk factors for diabetes mellitus.
    Sotalol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Spironolactone: (Moderate) Monitor for an increase in rosiglitazone-related adverse effects during concomitant use with spironolactone; adjust the dose of rosiglitazone based on clinical response. Coadministration may increase the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 substrate and spironolactone is a CYP2C8 inhibitor.
    Spironolactone; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor for an increase in rosiglitazone-related adverse effects during concomitant use with spironolactone; adjust the dose of rosiglitazone based on clinical response. Coadministration may increase the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 substrate and spironolactone is a CYP2C8 inhibitor.
    Sulfadiazine: (Moderate) Monitor blood glucose during concomitant metformin and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Moderate) It is possible that an increase in the exposure of rosiglitazone may occur when coadministered with drugs that inhibit CYP2C8 such as trimethoprim. Patients should be monitored for changes in glycemic control if any CYP2C8 inhibitors are coadministered with rosiglitazone. (Moderate) Monitor blood glucose during concomitant metformin and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Sulfasalazine: (Moderate) Monitor blood glucose during concomitant metformin and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Sulfinpyrazone: (Moderate) Rosiglitazone is metabolized by CYP2C9. It is possible for serum concentrations of rosiglitazone to rise when coadministered with drugs that inhibit CYP2C9, including sulfinpyrazone. Monitor serum glucose concentrations if rosiglitazone and sulfinpyrazone are coadministered. Dosage adjustments may be necessary.
    Sulfonamides: (Moderate) Monitor blood glucose during concomitant metformin and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and sulfonamide use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Sulfonylureas: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Sympathomimetics: (Moderate) Sympathomimetic agents tend to increase blood glucose concentrations when administered systemically. Monitor for loss of glycemic control when sympathomimetics are administered to patients taking thiazolidinediones. Sympathomimetics, through stimulation of alpha- and beta- receptors, increase hepatic glucose production and glycogenolysis and inhibit insulin secretion. Also, adrenergic medications may decrease glucose uptake by muscle cells. For treatment of cold symptoms, nasal decongestants may be preferable for short term, limited use (1 to 3 days) as an alternative to systemic decongestants in patients taking medications for diabetes.
    Tacrolimus: (Moderate) Patients should be monitored for worsening of glycemic control if therapy with tacrolimus is initiated in patients receiving antidiabetic agents. (Moderate) Tacrolimus has been reported to cause hyperglycemia. Furthermore, tacrolimus has been implicated in causing insulin-dependent diabetes mellitus in patients after renal transplantation. Tacrolimus may have direct beta-cell toxicity. Patients should be monitored for worsening of glycemic control if Tacrolimus is initiated in patients receiving antidiabetic agents.
    Tafenoquine: (Moderate) Consider the benefits and risks of coadministration of tafenoquine and metformin due to the potential for increased metformin concentrations and lactic acidosis. If coadministration cannot be avoided, monitor for metformin-related toxicities, and consider metformin dosage reduction, if needed. The effect of coadministration of tafenoquine on the pharmacokinetics of OCT2 and MATE substrates, like metformin, in humans is unknown; however, in vitro observations suggest the potential for increased concentrations of OCT2 and MATE substrates. Tafenoquine may interfere with these common renal tubular transport systems involved in the renal elimination of metformin.
    Tecovirimat: (Moderate) Monitor for an increase in rosiglitazone-related adverse effects during concomitant use with tecovirimat; adjust the dose of rosiglitazone based on clinical response. Coadministration may increase the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 substrate and tecovirimat is a weak CYP2C8 inhibitor.
    Tegaserod: (Moderate) Because tegaserod can enhance gastric emptying in diabetic patients, blood glucose can be affected, which, in turn, may affect the clinical response to antidiabetic agents. The dosing of antidiabetic agents may require adjustment in patients who receive GI prokinetic agents concomitantly. (Moderate) Tegaserod can enhance gastric emptying in diabetic patients, and blood glucose can be affected, which may affect the clinical response to antidiabetic drugs. Dosing of the antidiabetic agent may require adjustment in patients who receive GI prokinetic agents concomitantly.
    Telithromycin: (Moderate) Monitor for an increase in rosiglitazone-related adverse effects during concomitant use with telithromycin; adjust the dose of rosiglitazone based on clinical response. Coadministration may increase the exposure of rosiglitazone. Rosiglitazone is a CYP2C8 substrate and telithromycin is a weak CYP2C8 inhibitor.
    Telmisartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Telmisartan; Amlodipine: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Telmisartan; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Teriflunomide: (Moderate) Increased monitoring is recommended if teriflunomide is administered concurrently with CYP2C8 substrates, such as rosiglitazone. In vivo studies demonstrated that teriflunomide is an inhibitor of CYP2C8. Coadministration may lead to increased exposure to CYP2C8 substrates; however, the clinical impact of this has not yet been determined. Monitor for increased adverse effects.
    Testosterone: (Moderate) Changes in insulin sensitivity or glycemic control may occur in patients treated with androgens. In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, may decrease antidiabetic agent dosage requirements. Monitor blood glucose and HbA1C when these drugs are used together.
    Thiazide diuretics: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Diuretic-induced hypokalemia may also lead to hyperglycemia. Because of this, a potential pharmacodynamic interaction exists between thiazide diuretics and antidiabetic agents. It appears that the effects of thiazide diuretics on glycemic control are dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. However, patients taking antidiabetic agents should be monitored for changes in blood glucose control if such diuretics are added or deleted. Dosage adjustments may be necessary.
    Thyroid hormones: (Minor) Addition of thyroid hormones to antidiabetic or insulin therapy may result in increased dosage requirements of the antidiabetic agents. Blood sugars should be carefully monitored when thyroid therapy is added, dosages are changed, or if thyroid hormones are discontinued. (Minor) Thyroid hormone use may result in increased blood sugar and a loss of glycemic control in some patients. Interactions may or may not be clinically significant at usual replacement doses. Monitor blood sugars carefully when thyroid therapy is added, changed, or discontinued in patients receiving metformin.
    Timolol: (Moderate) Increased frequency of blood glucose monitoring may be required when a beta blocker is given with antidiabetic agents. Since beta blockers inhibit the release of catecholamines, these medications may hide symptoms of hypoglycemia such as tremor, tachycardia, and blood pressure changes. Other symptoms, like headache, dizziness, nervousness, mood changes, or hunger are not blunted. Beta-blockers also exert complex actions on the body's ability to regulate blood glucose. Some beta-blockers, particularly non-selective beta-blockers such as propranolol, have been noted to potentiate insulin-induced hypoglycemia and a delay in recovery of blood glucose to normal levels. Hyperglycemia has been reported as well and is possibly due to beta-2 receptor blockade in the beta cells of the pancreas. A selective beta-blocker may be preferred in patients with diabetes mellitus, if appropriate for the patient's condition. Selective beta-blockers, such as atenolol or metoprolol, do not appear to potentiate insulin-induced hypoglycemia. While beta-blockers may have negative effects on glycemic control, they reduce the risk of cardiovascular disease and stroke in patients with diabetes and their use should not be avoided in patients with compelling indications for beta-blocker therapy when no other contraindications are present.
    Tipranavir: (Moderate) New onset diabetes mellitus, exacerbation of diabetes mellitus, and hyperglycemia due to insulin resistance have been reported with use of anti-retroviral protease inhibitors. Onset averaged approximately 63 days after initiating protease inhibitor therapy, but has occurred as early as 4 days after beginning therapy. Diabetic ketoacidosis has occurred in some patients including patients who were not diabetic prior to protease inhibitor treatment. Patients on antidiabetic agents should be closely monitored for changes in glycemic control, specifically hyperglycemia, if protease inhibitor therapy is initiated. In addition, coadministration of atazanavir with rosiglitazone may result in elevated rosiglitazone plasma concentrations. Rosiglitazone is a substrate for CYP2C8; atazanavir is a weak inhibitor of CYP2C8.
    Tolazamide: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Tolbutamide: (Major) A maximum dose of 8 mg/day of rosiglitazone is recommended when used in combination with sulfonylureas; the incidence of adverse effects including hypoglycemia is increased with larger doses. In one clinical study, rosiglitazone 4 or 8 mg/day was added to failed glimepiride plus metformin therapy. The incidence of hypoglycemia (blood glucose concentrations <= 50 mg/dl) was 18.6% in the 4 mg/day group compared with 28% in the 8 mg/day group. In addition, 4 or 8 mg/day of rosiglitazone has been added to failed glyburide plus metformin therapy. The incidence of hypoglycemia was higher in the rosiglitazone (average dose 7.4 mg/day)+glyburide+metformin group (22%) when compared to the glyburide+metformin group (3%). Patients should be instructed to monitor blood glucose concentrations more frequently. Dosage adjustments may be indicated. (Moderate) Monitor blood glucose during concomitant sulfonylurea and metformin use; a sulfonylurea dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Topiramate: (Moderate) Consider more frequent monitoring of patients receiving metformin and concomitant topiramate due to increased risk for lactic acidosis. Carbonic anhydrase inhibitors, such as topiramate, frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. In healthy volunteers, metformin Cmax and AUC increased by 17% and 25%, respectively, when topiramate was added, and oral plasma clearance of topiramate appears to be reduced when administered with metformin. The clinical significance of the effect on the pharmacokinetics of metformin or topiramate are not known.
    Torsemide: (Minor) Hyperglycemia has been detected during torsemide therapy, but the incidence is low. Because of this, a potential pharmacodynamic interaction exists between torsemide and all antidiabetic agents, including metformin. Monitor blood glucose. (Minor) Hyperglycemia has been detected during torsemide therapy, but the incidence is low. Patients on antidiabetic medications should monitor their blood glucose regularly if torsemide is prescribed.
    Trandolapril: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Trandolapril; Verapamil: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin-converting enzyme (ACE) inhibitor use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Tranylcypromine: (Moderate) Monitor blood glucose during concomitant thiazolidinedione and monoamine oxidase inhibitor (MAOI) use; a thiazolidinedione dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Triamcinolone: (Moderate) Monitor blood glucose during concomitant corticosteroid and thiazolidinedione use; a thiazolidinedione dose adjustment may be necessary. Corticosteroids may increase blood glucose concentrations. Risk factors for impaired glucose tolerance due to corticosteroids include the corticosteroid dose and duration of treatment. Corticosteroids stimulate hepatic glucose production and inhibit peripheral glucose uptake into muscle and fatty tissues, producing insulin resistance. Decreased insulin production may occur in the pancreas due to a direct effect on pancreatic beta cells.
    Triamterene: (Minor) Triamterene can interfere with the hypoglycemic effects of antidiabetic agents. This can lead to a loss of diabetic control, so diabetic patients should be monitored closely.
    Triamterene; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Minor) Triamterene can interfere with the hypoglycemic effects of antidiabetic agents. This can lead to a loss of diabetic control, so diabetic patients should be monitored closely.
    Trilaciclib: (Moderate) Concomitant administration of metformin and trilaciclib may increase metformin exposure and increase the risk for lactic acidosis. If these drugs are given together, monitor for signs of metformin toxicity; metformin dose adjustments may be needed. Metformin is an OCT2 and MATE substrate; trilaciclib is an OCT2 and MATE inhibitor that may decrease metformin elimination by blocking renal tubular secretion.
    Trimethoprim: (Moderate) It is possible that an increase in the exposure of rosiglitazone may occur when coadministered with drugs that inhibit CYP2C8 such as trimethoprim. Patients should be monitored for changes in glycemic control if any CYP2C8 inhibitors are coadministered with rosiglitazone.
    Trospium: (Moderate) Trospium, if used concomitantly with metformin, may increase the risk of lactic acidosis. Cationic drugs that are eliminated by renal tubular secretion like trospium may decrease metformin elimination by competing for common renal tubular transport systems.
    Ultralente Insulin: (Moderate) Monitor blood glucose during concomitant metformin and insulin use; an insulin dose adjustment may be necessary. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Valsartan: (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Valsartan; Hydrochlorothiazide, HCTZ: (Moderate) Certain drugs, such as thiazide diuretics, tend to produce hyperglycemia and may lead to loss of glycemic control. The effects of thiazide diuretics on glycemic control appear to be dose-related and low doses can be instituted without deleterious effects on glycemic control. In addition, thiazide diuretics reduce the risk of stroke and cardiovascular disease in patients with diabetes. Patients receiving metformin should be monitored for changes in blood glucose control if any of these diuretics are added or deleted. Dosage adjustments may be necessary in some patients. (Moderate) Monitor blood glucose during concomitant metformin and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and angiotensin receptor blocker use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
    Vandetanib: (Moderate) Vandetanib could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Vandetanib increased the plasma concentrations of metformin, which is transported by the renal organic cation transporter type 2 (OCT2). Use caution and closely monitor for toxicities when administering vendetanib with metformin.
    Vemurafenib: (Moderate) Rosiglitazone is metabolized by CYP2C9 (minor pathway) and it is possible for serum concentrations of rosiglitazone to rise when coadministered with drugs that inhibit CYP2C9, including vemurafenib. Monitor serum glucose concentrations if rosiglitazone and vemurafenib are coadministered. Dosage adjustments may be necessary.
    Vonoprazan; Amoxicillin; Clarithromycin: (Moderate) The concomitant use of clarithromycin and antidiabetic agents can result in significant hypoglycemia. Careful monitoring of blood glucose is recommended. (Moderate) The concomitant use of clarithromycin and oral hypoglycemic agents can result in significant hypoglycemia. With certain hypoglycemic drugs such as the thiazolidinediones, inhibition of CYP3A enzyme by clarithromycin may be involved; however, CYP3A is not a major metabolism route for pioglitazone and rosiglitazone. Careful monitoring of glucose is recommended.
    Voriconazole: (Moderate) Because rosiglitazone is metabolized by CYP2C9, exaggerated therapeutic effect or hypoglycemia is possible if rosiglitazone is coadministered with voriconazole.
    Zafirlukast: (Moderate) In vitro data indicate that zafirlukast inhibits the CYP2C9 and CYP3A4 isoenzymes at concentrations close to the clinically achieved total plasma concentrations. Until more clinical data are available, zafirlukast should be used cautiously in patients stabilized on drugs metabolized by CYP2C9, such as rosiglitazone, especially those drugs with narrow therapeutic ranges.
    Zonisamide: (Moderate) Carbonic anhydrase inhibitors such as zonisamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Use of zonisamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.

    PREGNANCY AND LACTATION

    Pregnancy

    Metformin; rosiglitazone is not recommended for use during pregnancy. There is a lack of data describing the use of rosiglitazone during human pregnancy. Rosiglitazone has been reported to cross the human placenta and be detectable in fetal tissue; use during pregnancy is not recommended due to lack of data. Metformin has been studied as monotherapy during human pregnancy. The American College of Obstetricians and Gynecologists (ACOG) and the American Diabetes Association (ADA) continue to recommend human insulin as the standard of care in women with diabetes mellitus and gestational diabetes mellitus (GDM) requiring medical therapy; insulin does not cross the placenta. Per ACOG, in women who decline insulin therapy or are unable to safely administer insulin, metformin is the preferred second-line choice. Per the ADA, metformin monotherapy may be used to treat GDM as a treatment option; however, no long term safety data are available for any oral agent. Metformin may cause a lower risk of neonatal hypoglycemia and less maternal weight gain than insulin; however, some data suggest that metformin may slightly increase the risk of prematurity. The ADA notes that in some clinical studies, nearly 50% of GDM patients initially treated with metformin have needed the addition of insulin in order to achieve acceptable glucose control.

    Metformin; rosiglitazone should not be administered to a nursing woman. Animal data suggest that rosiglitazone may be excreted in milk, however, it is unknown if rosiglitazone or its metabolites are excreted in human milk. Due to the potential for adverse effects from rosiglitazone in the nursing infant, use during breast-feeding should be avoided. Metformin monotherapy may be considered, if appropriate. Animal data show that metformin is excreted into breast milk and reaches levels similar to those in plasma and small studies indicate that metformin is excreted in human breast milk. However, adverse effects of metformin exposure through breast milk on infant plasma glucose have not been reported in human studies. Furthermore, the use of metformin 2550 mg/day by mothers breast-feeding their infants for 6 months does not affect growth, motor, or social development; the effects beyond 6 months are not known. In all of these studies, the estimated weight-adjusted infant exposure to metformin ranged from 0.11 to 1.08% of the mother's dose. If blood glucose is not controlled on diet and exercise alone, insulin therapy may also be considered, or other oral hypoglycemics may be considered as possible alternatives during breast feeding. Because acarbose has limited systemic absorption, which results in minimal maternal plasma concentrations, clinically significant exposure via breast milk is not expected. Tolbutamide is usually considered compatible with breast-feeding. Glyburide may be a suitable alternative since it was not detected in the breast milk of lactating women who received single and multiple doses of glyburide. If oral hypoglycemics are used during breast feeding, the nursing infant should be monitored for signs of hypoglycemia, such as increased fussiness or somnolence.

    MECHANISM OF ACTION

    Metformin; rosiglitazone combines 2 antidiabetic agents with different mechanisms to improve glycemic control in patients with type 2 diabetes mellitus (DM). Metformin acts primarily by decreasing endogenous hepatic glucose production; rosiglitazone is an insulin sensitizer that acts by enhancing peripheral glucose utilization.
    Metformin: Metformin is an antihyperglycemic agent that improves glucose tolerance, lowering both basal and postprandial plasma glucose with mechanisms different from other classes of oral antidiabetic agents. Metformin decreases hepatic gluconeogenesis production, decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization. With metformin therapy, insulin secretion remains unchanged while fasting insulin levels and day-long plasma insulin response may actually decrease. Metformin improve glucose utilization in skeletal muscle and adipose tissue by increasing cell membrane glucose transport. This effect may be due to improved binding of insulin to insulin receptors since metformin is not effective in diabetics without some residual functioning pancreatic islet cells. Unlike the sulfonylureas, metformin rarely causes hypoglycemia since it does not significantly change insulin concentrations. An important distinction is that sulfonylureas increase insulin secretion thus making them useful in non-obese patients with type 2 diabetes mellitus (DM) while metformin improves insulin resistance, a common pathophysiologic finding in obese patients with type 2 DM. Metformin causes a 10% to 20% decrease in fatty-acid oxidation and a slight increase in glucose oxidation. Unlike phenformin, metformin does not inhibit the mitochondrial oxidation of lactate unless plasma concentrations of metformin become excessive (i.e., in patients with renal failure) and/or hypoxia is present. Clinically, metformin lowers fasting and postprandial hyperglycemia. The decrease in fasting plasma glucose is approximately 25% to 30%. Unlike oral sulfonylureas, metformin rarely causes hypoglycemia. Thus, metformin demonstrates more of an antihyperglycemic action than a hypoglycemic action. Metformin does not cause weight gain and in fact, may cause a modest weight loss due to drug-induced anorexia. Metformin also decreases plasma VLDL triglycerides resulting in modest decreases in plasma triglycerides and total cholesterol. Patients receiving metformin show a significant improvement in A1C, and a tendency toward improvement in the lipid profile, especially when baseline values are abnormally elevated.
    Rosiglitazone: Rosiglitazone is an oral thiazolidinedione; its primary action is enhancement of insulin sensitivity in adipose tissue, skeletal muscle and the liver. Rosiglitazone is a highly selective and potent agonist for the peroxisome proliferator activated receptor (PPAR-gamma), which regulates the transcription of a number of insulin responsive genes. PPAR receptors can be found in key target tissues for insulin action such as adipose tissue, skeletal muscle, and the liver. Clinically, rosiglitazone decreases plasma glucose concentrations, insulin concentrations, and glycosylated hemoglobin. Additional favorable metabolic effects include decreased hepatic glucose output and reduced free fatty acid serum concentrations. Unlike glimepiride, rosiglitazone enhances tissue sensitivity to insulin rather than stimulates insulin secretion.

    PHARMACOKINETICS

    Metformin; rosiglitazone is administered orally.
    Metformin: Metformin is distributed rapidly into peripheral body tissues and fluids and appears to distribute slowly into erythrocytes and to a deep tissue compartment (most likely GI tissues). The highest concentrations of metformin are found in the GI tract (10 times the concentrations in the plasma) and lower concentrations in the kidney, liver, and salivary gland tissue. Metformin is negligibly bound to plasma proteins. The apparent volume of distribution (V/F) of metformin following a single, 850 mg dose is 654 +/- 358 L. Steady-state concentrations of metformin are reached within 1 to 2 days and are generally less than 1 mcg/mL. Metformin is not metabolized by the liver and this fact may explain why the risk of lactic acidosis is much less for metformin than for phenformin (i.e., approximately 10% of patients have an inherited defect in the ability to metabolize phenformin). The drug is excreted by the kidneys, largely unchanged, through an active tubular process. Tubular secretion may be altered by many cationic drugs. Approximately 10% of an oral dose is excreted in the feces, presumably as unabsorbed metformin and about 90% of a dose is excreted by the kidneys within 24 hours. Biliary excretion does not occur. Although the average elimination half-life in the plasma is 6.2 hours in patients with normal renal function, metformin accumulates in the red blood cells, which leads to a much longer elimination half-life in the blood (17.6 hours).
    Rosiglitazone: Protein binding is approximately 99.8%, primarily to albumin. Metabolism is extensive with no unchanged drug detected in urine. The major routes of metabolism include N-demethylation and hydroxylation, followed by conjugation with sulfate and glucuronic acid. In vitro data show that rosiglitazone is predominantly metabolized by CYP2C8, with CYP2C9 serving as a minor pathway. Metabolites are active, but have significantly less activity than the parent compound and are not expected to contribute to the insulin-sensitizing activity of rosiglitazone. Radiolabeled studies suggest that approximately 64% and 23% of an administered dose is eliminated in the urine and in the feces, respectively. The elimination half-life of the parent drug is about 3 to 4 hours and is independent of the dose.
     
    Affected cytochrome P450 (CYP450) isoenzymes and drug transporters: Organic cationic transporter-2 (OCT2), multidrug and toxin extrusion (MATE1 and MATE2k), CYP2C8, CYP2C9
    Metformin: Drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT2]/multidrug and toxin extrusion [MATE1 and MATE2k] inhibitors such as ranolazine, vandetanib, dolutegravir, and cimetidine) could increase systemic exposure to metformin. Careful patient monitoring and dose adjustment of metformin and/or the potentially interfering drug is recommended with concurrent use.
    Rosiglitazone: In vitro data demonstrate that rosiglitazone is a CYP2C8 and CYP2C9 (minor) substrate. Rosiglitazone has not demonstrated clinically significant inhibition or induction of the hepatic CYP450 microsomal system enzymes. Theoretical interactions may be clinically significant when it is coadministered with some CYP2C8 inhibitors or inducers.

    Oral Route

    Bioequivalence between the separate metformin and rosiglitazone tablets and the combination products has been demonstrated. Food does not appear to significantly alter the pharmacokinetics of the combination product.
    Metformin: The bioavailability of metformin is 50% to 60%. Food decreases the extent and slightly delays the absorption of conventional metformin, however, it is recommended to be taken with meals.
    Rosiglitazone: Absorption of rosiglitazone occurs rapidly with an absolute bioavailability of 99%. The mean oral volume of distribution (Vss/F) is roughly 17.6 L. Peak plasma concentrations are achieved in about 1 hour after dosing. Food does not alter the pharmacokinetics of rosiglitazone.