Individuals who endure severe or excessive daytime sleepiness that persists even if they are able to experience a normal nighttime schedule of quality sleep belong to the group of thousands of other persons who are known to have central disorders of hypersomnolence. Considered a neurological disorder that can significantly impact the quality of life, idiopathic hypersomnia is one such condition. It has only recently received its first FDA-approved therapy, and promising additional research continues that may expand the potential options.

Sleep-related problems have been reported by almost half of the US population. With insomnia and excessive daytime sleepiness as the most commonly noted complaints, these types of problems can extend well beyond simply feeling tired and needing a good night of sleep. Memory issues, motor skill troubles, workplace difficulties, vehicular risks, emotional disturbances, and cardiovascular disorders are all potential circumstances for affected individuals. In certain scenarios, life-threatening situations could even emerge. Estimates of how many individuals cope with idiopathic hypersomnia range from 30,000 to 200,000 persons in the US. The lower end of that range may exist due to how difficult it can be to diagnose idiopathic insomnia definitively. The unfortunate likelihood is that therapies are not reaching many patients who are not yet properly identified.

The existing diagnostic criteria are steadily being honed to match more effective treatment plans to patients with precision. The American Academy of Sleep Medicine produces what is considered the authoritative clinical text for sleep disorders, the International Classification of Sleep Disorders (ICSD), currently in its third edition. According to the ICSD-3, six diagnostic criteria need to be met to diagnose idiopathic hypersomnia. These six are:

1. Daytime lapses into sleep or an irrepressible need to sleep daily for ≥3 months.
2. Insufficient sleep syndrome is confirmed absent, preferably via ≥1 week of wrist actigraphy.
3. Multiple Sleep Latency Test (MSLT) shows either <2 sleep-onset REM periods (REM sleep periods within 15 min of sleep onset) or zero sleep-onset REM periods if the REM latency on the preceding overnight sleep study was ≤15 min.
4. The presence of average sleep latency of ≤8 min on MSLT and/or the total 24-hr sleep time is ≥660 min (more typically 12-14 hr) when measured by a 24-hr sleep study that was performed after correcting any chronic sleep deprivation, or measured by wrist actigraphy recorded along with a sleep log and averaged over ≥7 days of unrestricted sleep.
5. No cataplexy.
6. There is not another condition (sleep disorder, medical or psychiatric disorder, or drug/medication use) that explains the hypersomnolence and test results.

The first therapy to treat idiopathic hypersomnia just came in the final half of 2021, when Xywav (calcium, magnesium, potassium, and sodium oxybates) oral solution received its FDA approval for the indication. Xywav is a central nervous system depressant indicated for the treatment of cataplexy or excessive daytime sleepiness in patients aged 7 or older who have narcolepsy and for treatment of idiopathic hypersomnia in adults. Due to risks for clinically significant respiratory depression and abuse and misuse of the drug, the prescribing information includes boxed warnings to alert to these and inform that the drug is available only through the Xywav and Xyrem REMS.

Much research is needed to increase understanding of the pathophysiology associated with sleep conditions such as idiopathic hypersomnia. Certain medications may be more effective in some patients than in others, so researchers will continue to uncover the path to optimal management of sleep disorders by learning about patterns among genetic and biochemical components across patients. Stay informed about drug information, including medications for treating idiopathic hypersomnia, by updating or registering your profile to receive email alerts and other critical drug information updates from PDR. You can also stay current by using the official PDR app, mobilePDR, available for free from your favorite app stores.