The US Food and Drug Administration (FDA) has approved Merck's Belsomra (suvorexant) for adults with insomnia who have difficulty falling asleep and/or staying asleep.

Belsomra (pronounced bell-SOM-rah) is a highly selective antagonist for orexin receptors. Orexin is a neurotransmitter found in a specific part of the brain that can help keep a person awake. The mechanism by which Belsomra exerts its therapeutic effect is presumed to be through antagonism of orexin receptors.

In the clinical trials to support efficacy, Belsomra was superior to placebo for sleep latency and sleep maintenance as assessed both objectively by polysomnography and subjectively by patient-estimated sleep latency. The recommended dose of Belsomra is 10 mg, taken no more than once per night and within 30 minutes of going to bed, with at least 7 hours remaining before the planned time of awakening. The total dose should not exceed 20 mg once daily.

“Today’s approval of Belsomra allows for the introduction of a new treatment option for patients suffering from insomnia,” said Dr. David Michelson, vice president, neurosciences, Merck Research Laboratories. “Belsomra is the result of more than a decade of Merck research in neuroscience and provides tangible evidence of our long-standing commitment to innovation."

The FDA has recommended Belsomra be classified by the US Drug Enforcement Administration (DEA) as a scheduled product. Earlier this year, the DEA proposed a Schedule IV drug classification under the Controlled Substances Act. The DEA has not yet issued a final decision on the scheduling for Belsomra and therefore product cannot become available before that decision.

Belsomra (suvorexant) is indicated for the treatment of insomnia characterized by difficulties with sleep onset and/or sleep maintenance.

Belsomra is expected to be available in late 2014 or early 2015.

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