Several readers have asked the Medical Letter to evaluate the effectiveness and safety of exogenous melatonin for treatment of insomnia and jet lag. Melatonin has not been approved by the US Food and Drug Administration (FDA), but is available in health food stores and apparently is being used as self-medication to treat a wide variety of disorders.

Over-the-counter products containing melatonin are widely used as sleep aids in children and adults.

The FDA has approved the melatonin receptor agonist tasimelteon (Hetlioz – Vanda) for treatment of non-24-hour sleep-wake disorder (non-24), which is common in totally blind persons. Tasimelteon is the first drug approved for this indication and the second melatonin receptor agonist approved for use in the US; ramelteon (Rozerem) was approved earlier for treatment of insomnia. Melatonin itself has not been approved by the FDA for any indication; it is available in the US as a dietary supplement and is promoted as a sleep aid.

Ramelteon (Rozerem - Takeda), a melatonin receptor agonist, has been approved by the FDA for treatment of insomnia characterized by difficulty falling asleep. Unlike all other prescription hypnotics, which are classified as schedule IV drugs, ramelteon is not a controlled substance.

Cognitive behavioral therapy for insomnia (CBT-I) is recommended for initial treatment of chronic insomnia. CBT-I includes stimulus control, sleep education and hygiene, sleep restriction, relaxation training, and cognitive therapy. When CBT-I alone is not effective, pharmacologic treatment should be added.

Millions of people now take herbal products and other "dietary supplements." The Physicians' Desk Reference has published a PDR for Herbal Medicines listing their ingredients and indications, and the Drug Topics Red Book lists their prices.

Zolpidem (Ambien - Sanofi-Aventis), a nonbenzodiazepine benzodiazepine receptor agonist, is the most frequently prescribed hypnotic in the US. As its patent approaches expiration, its manufacturer has received FDA approval to market an extended-release formulation of the drug, Ambien CR. The pharmacological rationale for doing so is that short-acting hypnotics like zolpidem are more effective at inducing sleep than they are at maintaining it.

The FDA has approved lemborexant (Dayvigo – Eisai), an orexin receptor antagonist, for treatment of sleep-onset and/or sleep-maintenance insomnia in adults. It is the second orexin receptor antagonist to be approved for this indication; suvorexant (Belsomra) was the first.

View the Table: Treatments Considered for COVID-19

The FDA has approved daridorexant (Quviviq – Idorsia), an orexin receptor antagonist, for treatment of sleep-onset and/or sleep-maintenance insomnia in adults. Daridorexant is the third orexin receptor antagonist to be approved for this indication; suvorexant (Belsomra) and lemborexant (Dayvigo) were approved earlier.