The drug suvorexant, sold as Belsomra, improves total sleep time in adults with probable Alzheimer’s disease and insomnia, according to a recent study published online in Alzheimer’s & Dementia.

Sleep disturbance and insomnia affect nearly 40% of adults with Alzheimer’s disease, and may further contribute to cognitive decline, reported the researchers. The current study is the latest in a series by Merck & Co., Kenilworth, NJ, to assess the medication’s use in people with dementia.

Investigators observed sleep in 136 patients who took suvorexant at 10 mg. for four weeks (dosage increase was allowed up to 20 mg.). Most had early-stage Alzheimer’s. Participants who took the drug experienced a mean 73-minute improvement in total sleep time compared to 45 minutes for a placebo group. They were also twice as likely as patients in the placebo group to show sleep time improvement of 60 minutes or greater, reported study lead W. Joseph Herring, M.D., Ph.D. 

Drowsiness was the most common adverse event (affecting 4.2% of participants), but the drug did not affect next-day cognitive or psychomotor functioning, observed Herring and colleagues.

Suvorexant was approved in 2014 by the U.S. Food and Drug Administration to treat insomnia in the general population.