The Food and Drug Administration released its review of the company's sleep aid, suvorexant, ahead of a public meeting on Wednesday. The pill works by temporarily blocking chemical messengers that keep people awake.
The FDA said company trials show suvorexant was better than placebo at helping people fall asleep and stay asleep. Regulators said Monday the drug's effectiveness was consistent across several doses tested by Merck & Co.
But patients taking the highest dose of the drug showed an eight-fold increase in daytime drowsiness, which could interfere with driving the next morning. Suvorexant was also associated with increased risk of suicidal thinking.