Many people with insomnia rely on over-the-counter sleep medications without fully understanding the risks of taking such drugs long term, according to Consumer Reports. 

The Food and Drug Administration requires instructions on OTC sleep med packages to tell consumers to see their doctor if insomnia persists for more than two weeks. But a 2015 Consumer Reports national survey of 4,023 adults found a troubling trend: Of the 20 percent who took an OTC medication within the past year to improve sleep, almost 1 in 5 respondents, or 18 percent, said they took it on a daily basis. Most concerning: 41 percent told us they used the drugs for a year or longer.

That’s a problem because diphenhydramine can cause constipation, confusion, dizziness, and next-day drowsiness, according to the drug’s FDA labeling. Another concern is the “hangover effect”—impaired balance, coordination, and driving performance the day after you’ve taken the drug, heightening the risk for falls and accidents. And in a January 2015 study in JAMA Internal Medicine, the frequent, long-term use of first-generation antihistamines, including diphenhydramine, was linked to an increased risk of dementia, including Alzheimer’s disease.