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My cat on methimazole is coughing. Is it allergies or medication?

Updated On September 23rd, 2025

Pet's info: Cat | Mixed Breed | Female | spayed | 8 lbs

My cat has just started methimazole for high thyroid levels. Since she started this medication, she started coughing periodically. She has had allergies in the past, so I am unsure if she is reacting to the medication, having allergy problems, or if it is something all together separate. I plan on calling the vet on Monday for an appointment. In the meantime, should give her her allergy medication. She has chlorpheniramine for allergies.

1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on April 29th, 2017

Your poor cat! I'm wondering if it is something completely differing causing her coughing. Coughing can be a sign of heart disease, and it's a good idea that you call the vet on Monday for an appointment. I'd recommend a physical exam, geriatric blood panel, urinalysis, and chest x-rays. I would hold off on giving her the allergy medications until after you speak to your vet.

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