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Ask Dr. Michael Salkin Your Own Question
Dr. Michael Salkin
Dr. Michael Salkin, Veterinarian
Category: Dog Veterinary
Satisfied Customers: 28425
Experience:  University of California at Davis graduate veterinarian with 45 years of experience
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Just reading about giving both Zyrtec and Benadryl in the

Customer Question

Just reading about giving both Zyrtec and Benadryl in the same day to my yorkie who is just sick with some allergy thing.
Submitted: 1 year ago.
Category: Dog Veterinary
Expert:  Dr. Michael Salkin replied 1 year ago.

I'm sorry that your question wasn't answered in a timely manner. Both Zyrtec (ceterizine) and Benadryl (diphenhydramine) are H1 receptor blocking antihistamine agents and so using both in the same day isn't expected to cause anything more than over-sedation. We avoid dosing with two different antihistamines because should there be an adverse effect - paradoxical agitation rather than sedation, for example - we won't know which antihistamine was responsible or if the combination of the antihistamines were responsible. It's important to note that antihistamines are not reliably effective when addressing allergic dermatitis in dogs. Less than 10% of atopic (allergic to environmental allergens such as pollens, molds, dust, and dust mites, etc.) benefited from an antihistamine plus fatty acid supplements in a large recent study.

The grey matter might represent an allergic conjunctivitis but isn't pathognomonic (specifically indicative) of an allergic conjunctivitis. It's best to have eyes checked promptly because they can "go south" in a hurry. I'd like to see a close up photo of that sore on her lower lip. Can you upload a photo of it to our conversation? You can use the paperclip icon in the toolbar above your message box (if that icon is visible) or you can use an external app such as or I can be more accurate for you if I can see what you're seeing.

It's late here now and I have to leave my computer but I promise to reply in the morning if need be.

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