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.

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.

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.

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.

View the Expanded Table: Some Oral Drugs for Chronic Insomnia

The FDA has approved a new low-dose formulation of the tricyclic antidepressant doxepin (Silenor – Somaxon) for treatment of insomnia associated with sleep maintenance. The manufacturer claims that this dose retains the hypnotic effect of doxepin, without typical tricyclic adverse effects. Doxepin is available generically in higher-strength capsules and in a liquid formulation.

The FDA has approved suvorexant (Belsomra – Merck), the first orexin receptor antagonist to become available in the US, for treatment of sleep-onset and/or sleep-maintenance insomnia.

View the Expanded Table: Some Drugs for Altitude Illness, Jet Lag, and Motion Sickness

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.

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.