Benadryl Side Effects in Dogs

Benadryl relieves allergic symptoms. Developed for people, this antihistamine offers benefits for some dogs. Veterinarians suggest the medication for a variety of canine ailments including allergies, skin problems and motion sickness. Watch for side effects when your dog is taking benadryl or its generic version.


The generic name for benadryl is diphenhydramine hydrochloride. Your dog's size and health determines benadryl dosage.


Watch for excess drowsiness or disorientation in your dog. Though the dog may benefit from the mild tranquillising effect of benadryl, too much sedation is not healthy.

Stomach Upset

Though diphenhydramine can counteract problems such as car sickness, it could make your dog throw up. Giving the medication with food helps calm her stomach.


Be aware of appetite changes. If your dog does not eat after taking benadryl, you may need to feed him before giving the antihistamine next time.


Tell your vet about other medicationsyou give your dog. Combining drugs such as tranquillisers with the diphenhydramine can have too strong an effect and she may have breathing difficulty or other symptoms of overdose.


Do not use diphenhydramine that is combined with a sinus or pain reliever. The extra ingredients are bad for your dog and can poison him.


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About the Author

Phyllis Benson is a professional writer and creative artist. Her 25-year background includes work as an editor, syndicated reporter and feature writer for publications including "Journal Plus," "McClatchy Newspapers" and "Sacramento Union." Benson earned her Bachelor of Science degree at California Polytechnic University.