Dear Christopher Cat
My cat Rupert requires Tapazole to control his hyperthyroidism. I have arthritis and it’s hard for me to pill him, so my veterinarian prescribed methimazole cream which I rub onto his ears. How effective is this product?
Methimazole is the generic name of Tapazole, a drug that reduces excessive thyroid hormone production in cats with hyperthyroidism. It works well whether administered transdermally (which means “through the skin”) or orally.
Transdermal methimazole is usually applied to the inner surface of the cat’s ear flap twice daily. It’s best to alternate ears with each dose, removing any crusted material on the ear flap prior to administration.
To be sure the drug isn’t absorbed through your own skin, wear a glove or finger cot, and wash your hands afterwards.
Periodically, your veterinarian will check the level of thyroid hormone in Rupert’s blood to fine tune the methimazole dose. Rupert’s blood work will be your best indication of how well the medication is working.
In a small study comparing cats given methimazole orally and transdermally, 82 percent of the cats taking oral methimazole had normal thyroid function in four weeks, while 67 percent of cats receiving the transdermal version had normal thyroid function in that time.
Side effects were similar, except that 24 percent of cats receiving oral methimazole experienced poor appetite or vomiting compared to four percent of cats given the transdermal medication.