Doxylamine is a first-generation antihistamine and sedative-hypnotic. It is commonly sold in the United States and elsewhere as a sleep aid.
Compared to diphenhydramine (Benadryl), doxylamine has a faster onset (20-30 minutes versus 45 minutes) and a shorter duration. Consequently, it is possible that doxylamine is more effective as a sleep aid for people who have trouble falling asleep but are able to stay asleep. Diphenhydramine may be more beneficial to people who fall asleep easily but have problems staying asleep.Doxylamine may be more effective than phenobarbital as a sleep aid. It may also behave as an anxiolytic, and antiemetic for pregnant women.