Ramelteon is a selective melatonin receptor (MT(1) and MT(2)) agonist that has been approved by the US Food and Drug Administration for the treatment of insomnia characterized by difficulty with sleep onset. It is the only approved sleep-promoting medication that does not have a direct sedating effect, but rather enhances sleep through effects on sleep regulatory mechanisms within the suprachiasmatic nucleus. Ramelteon has been shown to have no abuse liability and therefore is not scheduled by the U.S. Drug Enforcement Agency as a controlled substance. It is available as an 8 mg tablet, which should be taken approximately 30 minutes prior to bedtime. The FDA approval contains no limitation on how long the medication may be prescribed.
Keywords: circadian rhythm; insomnia; melatonin receptors; ramelteon; sleep-wake cycle.