Sleep Disorders Treatment Using Diphenhydramine or Benadryl as a Sleep Aid Insomnia Medication Information About This Over-The-Counter Sleeping Pill By Brandon Peters, MD facebook twitter Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist. Learn about our editorial process Brandon Peters, MD Medically reviewed by Medically reviewed by Sanja Jelic, MD on November 20, 2019 Sanja Jelic, MD is board-certified in pulmonary disease, sleep medicine, critical care medicine, and internal medicine. She is an assistant professor and attending physician at Columbia University College of Physicians and Surgeons in New York, NY. Learn about our Medical Review Board Sanja Jelic, MD on November 20, 2019 Print Table of Contents View All Uses How It Works Contraindications Side Effects Warnings and Interactions The over-the-counter medication diphenhydramine is found in many sleeping pills intended for insomnia treatment. It is the sleep-inducing element in many medications used as sleep aids. Its use does not require a prescription, so it is sometimes used as the initial option for the treatment of acute insomnia to help initiate and maintain sleep. Due to the potential for side effects, especially among older people, alternatives may be sought if chronic insomnia persists. Brand New Images / Stone / Getty Images Uses Diphenhydramine has many potential uses. As it does cause sleepiness, it is only recommended for short-term treatment of insomnia or acute insomnia. By definition, this is insomnia that occurs for less than three months. It is one of the ingredients found in multiple sleep aids: Tylenol PMAdvil PMAleve PMZzzQuilBenadryl It may help you get to sleep or stay asleep. However, there is little evidence that diphenhydramine actually improves insomnia, and it may cause sleepiness the day after taking it. Doctors do not recommend the routine or chronic use of diphenhydramine to treat insomnia. In addition to its use as a sleep aid, diphenhydramine is often administered to relieve allergies or treat allergic reactions, and it can be helpful in preventing motion sickness. It is also used to alleviate extrapyramidal symptoms, which may occur as a side effect of other medications. How It Works Diphenhydramine is part of a class of medications called antihistamines. It works at the level of neurotransmitters, which are the chemical messengers within the brain. It allows the neurotransmitter called histamine to build up in the spaces called synapses that are present between nerve cells. This leads to sedative effects and is accomplished by blocking its uptake into nearby cells. Diphenhydramine works both centrally within the brain as well as in peripheral nerve cells in other parts of the body. It possesses other effects and can suppress a cough, nausea, and uncontrolled movements called dyskinesis. Precautions and Contraindications Children less than 2 years old should not use diphenhydramine. Additionally, caution should be used when this medication is used by children younger than 6 years old and by the elderly. Why Older People Should Avoid Diphenhydramine If you have increased intraocular pressure, such as in glaucoma, you should use diphenhydramine cautiously. Other conditions may also require caution, including individuals who have: AsthmaBowel or bladder obstructionChronic obstructive pulmonary diseaseHeart diseaseHigh blood pressureHyperthyroidismPeptic ulcer diseasePneumoniaProstate enlargement If you have these conditions, you may wish to discuss your risk with your doctor before starting to use the medication. Side Effects Some side effects that may commonly occur with diphenhydramine include: Delirium (confusion)Diminished coordination or cognitive functionDrowsinessDizzinessIncreased intraocular pressure (similar to glaucoma)HeadacheStomach discomfortThick lung secretionsDry mouth or noseHyperactivityConstipationDifficulty urinatingLow blood pressureBlurry or double visionRapid or irregular heart rateSensitivity to lightSweatingErectile dysfunction (impotence) Severe With the use of any drug, there are also risks of serious side effects. These occur more rarely. When using diphenhydramine, these may include: Anaphylaxis (severe allergic reaction including difficulty breathing)Low blood cell counts (agranulocytosis, anemia, thrombocytopenia, and leukopenia)Abnormal heart rhythmsSeizuresToxic psychosisAcute labyrinthitis (inner ear problems) Warnings and Interactions As noted above, certain people should use diphenhydramine with caution, or not at all. It is an over-the-counter medication, so the risks are thought to be slightly lower compared to other prescription medications. Harm to a developing fetus during pregnancy is possible but unlikely, and diphenhydramine is probably safe in lactation and breastfeeding, though caution is advised. Diphenhydramine has the potential to interact with some other drugs, especially those that affect the brain, so you may wish to review your medications with your doctor or pharmacist before using it. A Word From Verywell If you experience any difficulties, you should be in close contact with your primary health provider. If you suffer from chronic insomnia that occurs at least three nights per week and lasts at least two weeks, consider the use of cognitive behavioral therapy for insomnia (CBTI) to resolve the condition instead. You can use our Doctor Discussion Guide below to start a conversation with your doctor about the most appropriate treatment approach. Insomnia Doctor Discussion Guide Get our printable guide for your next doctor's appointment to help you ask the right questions. Download PDF Email the Guide Send to yourself or a loved one. Sign Up This Doctor Discussion Guide has been sent to {{form.email}}. There was an error. Please try again. Was this page helpful? Thanks for your feedback! Tossing and turning night over night can have a big impact on your quality of life. Our free guide can help you get the rest you need. Sign up for our newsletter and get it free. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Schroeck JL, Ford J, Conway EL, et al. Review of safety and efficacy of sleep medicines in older adults. Clin Ther. 2016;38(11):2340-2372. doi:10.1016/j.clinthera.2016.09.010 Albert SM, Roth T, Toscani M, Vitiello MV, Zee P. Sleep health and appropriate use of OTC sleep aids in older adults-recommendations of a Gerontological Society of America workgroup. Gerontologist. 2017;57(2):163–170. doi:10.1093/geront/gnv139 Sateia MJ, Buysse DJ, Krystal AD, Neubauer DN, Heald JL. Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults: An American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med. 2017;13(2):307–349. doi:10.5664/jcsm.6470 Food and Drug Administration. Diphenhydramine hydrochloride injection, USP label. Updated January 4, 2013. Farzam K, O'Rourke MC. Antihistamines. In: StatPearls. Updated September 27, 2019. NIH Toxicology Data Network. Diphenhydramine. Updated September 4, 2014. Brzezińska-wcisło L, Zbiciak-nylec M, Wcisło-dziadecka D, Salwowska N. Pregnancy: a therapeutic dilemma. Postepy Dermatol Alergol. 2017;34(5):433-438. doi:10.5114/ada.2017.71108 Additional Reading Epocrates. Diphenhydramine.