Is it OK to use over-the-counter antihistamines to treat insomnia? I'd like to avoid prescription sleep aids.
Answers from Eric J. Olson, M.D.
Antihistamines can cause drowsiness, which might help you fall asleep for a few nights — but routine use of antihistamines for insomnia isn't recommended.
Antihistamines, mainly used to treat symptoms of hay fever or other allergies, induce drowsiness by working against histamine, a chemical produced by the central nervous system. In fact, most over-the-counter sleep aids contain antihistamines. These sleep aids are intended to be used for only two to three nights at a time, however, such as when stress, travel or other disruptions keep you awake.
Tolerance to the sedative effects of antihistamines can develop quickly. As a result, the longer you take them, the less likely they are to make you sleepy. Side effects might include daytime drowsiness, dry mouth and dizziness.
Also, diphenhydramine and doxylamine — sedating antihistamines found in various over-the-counter sleep aids — aren't recommended for people who have closed-angle glaucoma, asthma, chronic obstructive pulmonary disease or severe liver disease.
Diphenhydramine and doxylamine have anticholinergic properties that make them poor choices for older adults. Recent studies have shown that anticholinergics might increase the risk of dementia. These drugs also have numerous side effects in older adults, such as confusion, hallucinations, dry mouth, blurred vision, constipation, nausea, impaired sweating, inability to empty the bladder completely (urinary retention) and rapid heart rate (tachycardia).
Keep in mind that most sleep aids aren't recommended for women who are pregnant or breast-feeding.
If you're struggling with chronic insomnia, don't rely on antihistamines or other over-the-counter sleep aids for a good night's sleep. Start with lifestyle changes instead:
- Follow a regular sleep schedule.
- Avoid caffeine and daytime naps.
- Include physical activity in your daily routine.
- Avoid prolonged use of smartphones, tablets, laptops and other light-emitting screens before bedtime.
- Manage stress.
If you continue to have trouble falling or staying asleep, consult your doctor. In addition to lifestyle changes, your doctor might recommend ways to make your sleeping environment more conducive to sleep or suggest behavior therapy to help you learn new sleep habits. In some cases, short-term use of prescription sleep aids might be recommended as well.
Jan. 10, 2018
See more Expert Answers
- Bonnet MH, et al. Treatment of insomnia in adults. https://www.uptodate.com/contents/search. Accessed Jan. 3, 2018.
- Kryger MH, et al., eds. Pharmacologic treatment of insomnia: Other medications. In: Principles and Practice of Sleep Medicine. 6th ed. St. Louis, Mo.: Elsevier Saunders; 2017. https://www.clinicalkey.com. Accessed Jan. 3, 2018.
- Roussin A, et al. Misuse and dependence on non-prescription codeine analgesics or sedative H1 antihistamines by adults: A cross-sectional investigation in France. PLOS One. 2013;8:e76499. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0076499. Accessed Jan. 3, 2018.
- Daroff RB, et al. Sleep and its disorders. In: Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, Pa.: Saunders Elsevier; 2016. https://www.clinicalkey.com. Accessed Jan. 3, 2018.
- Owens JA. Behavioral sleep problems in children. https://www.uptodate.com/contents/search. Accessed Jan. 3, 2018.
- Chuang YF, et al. Midlife anticholinergic drug use, risk of Alzheimer's disease, and brain atrophy in community-dwelling older adults. Alzheimer's and Dementia 2017;3:471.
- Dauphinot V, et al. Anticholinergic drugs and functional, cognitive impairment and behavioral disturbances in patients from a memory clinic with subjective cognitive decline or neurocognitive disorders. Alzheimer's Research and Therapy. 2017;9:58.
- Ropper AH, et al. Sleep and its abnormalities. In: Adams & Victor's Principles of Neurology. 10th ed. New York, N.Y.: The McGraw-Hill Companies; 2014. http://accessmedicine.mhmedical.com. Accessed Jan. 3, 2018.
- Rochon PA. Drug prescribing for older adults. https://www.uptodate.com/contents/search. Accessed Jan. 3, 2018.