Diphenhydramine
Siladryl is a brand-name antihistamine medication containing diphenhydramine. It is commonly used to treat allergic reactions, hay fever symptoms, and as a short-term sleep aid. This medication works by blocking histamine receptors in the body, providing relief from symptoms such as sneezing, itching, watery eyes, and runny nose.
Siladryl is an antihistamine used for allergy relief and as a sleep aid.
Key facts at a glance
- RxNorm
- 219896
- Generic
- Siladryl
- Class
- brand-name
- Brands
- —
- 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.
Siladryl is used to temporarily relieve symptoms caused by allergies, including sneezing, runny nose, itchy or watery eyes, and skin itching or hives. It is also commonly used as a nighttime sleep aid for occasional insomnia.
As an antihistamine, Siladryl works by blocking the action of histamine—a substance in the body that causes allergic symptoms. It binds to histamine H1 receptors, preventing histamine from triggering allergic reactions and inflammatory responses.
This medication may cause drowsiness, so activities requiring alertness should be avoided until you know how the medication affects you. It should not be used with alcohol or other sedatives. Consult a healthcare provider before use if you have glaucoma, breathing problems, or are taking other medications. Not recommended for use in children under 12 without medical advice.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
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 July 26, 2026. · Read our editorial policy