Is it OK to use over-the-counter antihistamines to treat insomnia? I'd like to avoid prescription sleep aids.
Answer From Eric J. Olson, M.D.
While some over-the-counter antihistamines can cause drowsiness, routinely using them to treat insomnia isn't recommended.
Antihistamines, mainly used to treat symptoms of hay fever or other allergies, can induce drowsiness by working against a chemical produced by the central nervous system (histamine). These medications can be useful in certain situations, such as for treating sleeplessness related to travel.
However, 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, the sedating antihistamines diphenhydramine and doxylamine have anticholinergic properties that make them poor choices for older adults. Research suggests that anticholinergics might increase the risk of dementia. In older adults these drugs also can cause confusion, hallucinations, dry mouth, blurred vision, constipation, nausea, impaired sweating, inability to empty the bladder completely (urinary retention) and rapid heart rate (tachycardia).
Diphenhydramine and doxylamine also aren't recommended for people who have closed-angle glaucoma, asthma, chronic obstructive pulmonary disease or severe liver disease.
If you're struggling with chronic insomnia, don't rely on antihistamines for a good night's sleep.
Dec. 09, 2021
- Bonnet MH, et al. Behavioral and pharmacologic therapies for chronic insomnia in adults. //www.uptodate.com/contents/search. Accessed Aug. 5, 2019.
- Kryger MH, et al., eds. Pharmacologic treatment of insomnia: Other medications. In: Principles and Practice of Sleep Medicine. 6th ed. Elsevier Saunders; 2017. //www.clinicalkey.com. Accessed Aug. 5, 2019.
- 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; 10.1186/s13195-017-0284-4.
- Daroff RB, et al. Sleep and its disorders. In: Bradley's Neurology in Clinical Practice. 7th ed. Saunders Elsevier; 2016. //www.clinicalkey.com. Accessed Aug. 5, 2019.
- Owens JA. Behavioral sleep problems in children. //www.uptodate.com/contents/search. Accessed Aug. 5, 2019.
- 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; doi: 10.1016/j.trci.2017.06.004.
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Content
For people who take an antihistamine such as Benadryl for a cold or allergies, drowsiness is often a welcome side effect. But a Baylor College of Medicine sleep expert cautions against turning to this type of medication as a sleep aid.
“Many allergy sufferers know that antihistamines work for their symptoms but also make them sleepy. People sometimes turn to these medications to help them sleep, even when they’re not sick. But the use of medication to force children or adults to sleep is generally not the best idea,” said Dr. Philip Alapat, assistant professor of medicine.
Antihistamines have side effects that include altered mental state, urinary retention and dry mouth. While these side effects are generally mild and well tolerated in young patients without other medical problems, they can pose a risk, especially for the elderly.
“Use of antihistamines can lead to sleep walking and other parasomnias. That can definitely occur with Benadryl just as with other hypnotic agents like Ambien,” Alapat said.
While antihistamines may help you to fall asleep, overall sleep quality is usually not very good, he said. Sometimes, they even have the opposite affect and cause hyperactivity, especially in children.
“Using Benadryl or any antihistamine for sleep has no long term benefit,” Alapat said. “Most people develop a tolerance very quickly.”
Many over-the-counter sleep aids are simply antihistaminic drugs repackaged and labeled as something to help you achieve sleep, he cautioned.
Alapat recommends that people who suffer from long-term insomnia visit a physician or sleep disorders specialist to address the problem, which could result from medical issues such as obstructive sleep apnea, depression or circadian rhythm disorders.
“For many people, insomnia is short-term due to a stressful event or family problems. In this context, for a brief period it’s not unreasonable to consider pharmacological agents to help you get to sleep but even in this situation people should consult a physician to determine what medication might work best,” Alapat said.