Merck & Co. has won federal approval for a new type of sleeping pill designed to help people with insomnia stay asleep.
The tablet, Belsomra, works by temporarily blocking chemicals known as orexins that control the sleep cycle and can keep people awake at night. It's unclear whether the new drug is safer or more effective than older drugs because it was tested against a dummy pill, rather than other sleeping medications.
The Food and Drug Administration approved the drug in four different doses for various degrees of insomnia. The agency notes that patients who took the highest dose, 20 milligrams, experienced drowsiness and difficulty driving the following morning. The FDA says doctors should warn patients taking that dose against next-day driving or activities that require full concentration.