The FDA says an experimental Merck drug, suvorexant, helps patients fall asleep but has worrisome side effects, including suicidal thinking. The FDA said company trials showed the pill consistently worked better than a placebo. But patients taking higher doses had an eight-fold increase in daytime drowsiness that interfered with driving. Four women had to stop a driving test. And over 12 months, eight cases of suicidal thinking or behavior were reported. It’s possible the FDA will allow the drug to be used only in lower doses.