Antihistamines for Cats

Updated October 06, 2017

Cats can be allergic to substances in their food, their environments, or the air they breathe. A range of treatments will either eliminate or control allergic reactions in 9 of 10 feline allergy sufferers, according to Among the most effective treatments are antihistamines.


The antihistamines routinely prescribed for cats effectively reduce symptoms in about 70 per cent of animals and are even more effective when combined with fatty acid supplementation.


Diphenhydramine (benadryl), chlorpeniramine (Chlor-trimeton), and clemastine (Tavist) keep histamines from attaching to a cat's cell receptors so they can't cause allergy symptoms.

Side Effects

All three antihistamines may have a sedative effect. Benadryl and Tavist cause dry mouth, while Chlor-trimeton may give your cat diarrhoea. Extremely itchy cats might benefit from mild sedation.


The most effective way to use an antihistamine, advises the ASPCA, is as a preventive. Give it to your cat before he will be in a situation likely to trigger his allergies.


Cats can't tolerate antihistamines containing pseudophedrine, according to the University of Illinois College of Veterinary Medicine.

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About the Author

Passionate for travel and the well-written word, Judy Wolfe is a professional writer with a Bachelor of Arts in English literature from Cal Poly Pomona and a certificate in advanced floral design. Her thousands of published articles cover topics from travel and gardening to pet care and technology.