Suvorexant: a dual orexin receptor antagonist for the treatment of sleep onset and sleep maintenance insomnia.

OBJECTIVE: To review the efficacy, safety, and pharmacology data available for suvorexant and determine its role in therapy as compared with other agents available for the treatment of insomnia.

DATA SOURCES: A PubMed search using the terms suvorexant and MK-4305 (the original name given to suvorexant during early trials) was conducted in December 2014 to identify initial literature sources. No time frame was used for exclusion of older trials.

STUDY SELECTION AND DATA EXTRACTION: Animal studies and trials written in a language other than English were excluded. Abstracts of the remaining trials were evaluated for determination of relevance to this review. References from these studies along with suvorexant prescriber information were used to identify additional literature.

DATA SYNTHESIS: Three randomized, double-blind, placebo-controlled clinical trials were identified showing suvorexant to be safe, effective, and tolerable for the treatment of insomnia. After 4 weeks of therapy, relative to placebo, the 10- and 20-mg doses improved subjective total sleep time (22.3 and 49.9 minutes, respectively), wake after sleep onset (-21.4 and -28.1 minutes), and latency to persistent sleep (-2.3 and -22.3 minutes).

CONCLUSION: Suvorexant is the first dual orexin receptor antagonist approved for the treatment of insomnia. Clinical trials have shown that it is relatively safe and effective for the treatment of both sleep onset and sleep maintenance at doses of 20 mg or less. Higher doses were studied but not approved because of concerns for next-day somnolence and effects on driving. Further studies are needed to assess this medication in patients with a history of addiction, because they were excluded from clinical trials, as well as to compare suvorexant with other insomnia medications available because no head-to-head studies have yet been conducted. However, its novel mechanism of action and theoretically lower addiction liability make suvorexant an appealing new option.