Diphenhydramine Hydrochloride
Diphenhydramine Hydrochloride is a first-generation antihistamine that provides relief from allergy symptoms such as sneezing, itching, and runny nose. It is also commonly used as a sleep aid and for the temporary relief of cold symptoms. This medication is available over-the-counter and by prescription in various forms.
Diphenhydramine is an antihistamine used for allergies, cold symptoms, and as a sleep aid that works by blocking histamine receptors.
Key facts at a glance
- RxNorm
- 1362
- Generic
- Diphenhydramine Hydrochloride
- Class
- pin-variant
- Brands
- Percogesic Reformulated Jan 2011, Wal-Dryl, Compoz, Wal-Dryl Childrens, Wal-Dryl-D, Wal-Dryl Allergy, Wal-Som Maximum Strength, Nytol, Banophen Cream, Sleep-Eze
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Treats allergic conditions including hay fever, allergic conjunctivitis, and skin allergies; relieves cold symptoms such as sneezing and runny nose; used as a temporary sleep aid; and may be used for motion sickness and as an adjunct in anaphylaxis treatment.
Blocks H1 histamine receptors in the body, preventing histamine from causing allergic symptoms like swelling, itching, and increased mucus production.
Causes drowsiness in most users; avoid alcohol and operating machinery; may cause dry mouth and urinary retention; not recommended for elderly patients with BPH or glaucoma; prolonged use as a sleep aid is not advised.
Official drug label
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This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy