Some over-the-counter medicines to help a person sleep include diphenhydramine and doxylamine succinate, states Mayo Clinic. Also available over-the-counter is melatonin, a hormone that helps control a person's natural sleep cycle, and valerian, a supplement derived from plants that some people claim helps promote sleep.Continue Reading
Diphenhydramine is a type of sedating antihistamine, according to Mayo Clinic. Side effects associated with the medicine are blurred vision, dry mouth, daytime drowsiness, constipation and urinary retention. Doxylamine succinate is another type of sedating antihistamine, with many similar side effects.
Research into the effectiveness of melatonin and valerian is still ongoing, according to Mayo Clinic. Side effects of melatonin include headache and daytime drowsiness. In general, valerian appears to have no side effects.Learn more about Medications & Vitamins