Suvorexant, a Dual Orexin Receptor Antagonist for the Management of Insomnia

Insomnia is characterized subjectively and may consist of a variety of complaints, including difficulty falling asleep, difficulty maintaining sleep, or experiencing nonrestorative sleep. Despite a number of available treatments, insomnia is the most common medical complaint in general practice.1 It affects up to 30% of the adult population.2 It is also a major risk factor for anxiety disorder, substance abuse, and major depression, and it may lead to a decreased quality of life.2 A variety of treatment options are available for insomnia. The most common pharmacological interventions are benzodiazepines (BZDs) and the non-BZD gamma-amino-butyric acid (GABA)–acting hypnotics such as zolpidem (Ambien, Sanofi), eszopiclone (Lunesta, Sunovion), and zaleplon (Sonata, Pfizer).1 Other less frequently prescribed agents include sedating antidepressants, melatonin agonists, and antihistamines.2 Diminished efficacy and negative side effects limit the use of these treatment options for many patients. Suvorexant (MK-4305, Merck), an orexin receptor antagonist (ORA), is the first in a new class of drugs in development for the treatment of insomnia. The tablets promote the natural transition from wakefulness to sleep by inhibiting the wakefulness-promoting orexin neurons of the arousal system.1 Suvorexant improves sleep onset and sleep maintenance. This unique alternative has a favorable tolerability and limited side-effect profile.2