Antihistamines for severe allergic reactions

Antihistamine tablets such as diphenhydramine hydrochloride (Benadryl) or chlorpheniramine maleate (Chlor-Trimeton) are included in allergy kits to stop or reduce itching, hives, sneezing and wheezing, and other symptoms caused by an allergic reaction. They are not a substitute for an epinephrine shot.

Many allergic symptoms, such as hives and wheezing, occur when a chemical called histamine is released as part of the allergic reaction to an allergen. Antihistamine medications block the release of histamine.

Antihistamines can make people sleepy or make it harder for them to concentrate. These medications should be used carefully by people who need to drive or operate heavy machinery. Other side effects include dry mouth, nausea and vomiting, restlessness or irritability (especially in children), inability to urinate, and blurred vision.



Author: Caroline Rea, RN, BS, MSLast Updated: January 22, 2008
Medical Review: William M. Green, MD - Emergency Medicine
Harold S. Nelson, MD - Allergy and Immunology

© 1995-2008 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

Click here to learn about Healthwise