Pharmacy Spotlight: Methimazole
Drs. Foster & Smith Educational Staff

Spotlight on Methimazole

  • Medication type: Antithyroid drug

  • Active ingredient: Methimazole

  • Dosage form: Tablets

  • Manufacturer: Sandoz (Tablets)

  • Brand name: Tapazole® (Tablets)

  • Major use: The medication of choice for treating hyperthyroidism in cats.

  • How it works: Methimazole prevents the thyroid gland from producing excessive amounts of thyroid hormone.

Methimazole SUCCESS STORY:

Cat's Name: Zoe
Breed: Persian
Persian CatAge: 12 years

Her story: Zoe was one of three cats in a household very partial to felines. Zoe, however, was special; an all white cat, she was known for her elegance and persnickety ways. Her licking would continue long after her little chums tired of the grooming routine.

It was a change, then, that her owners could not miss. The little "princess" began to take on an unkempt, dull appearance. At first they attributed this to loss of coat, but when they realized that she was also losing weight – in spite of the fact that she was eating and drinking as usual – they became concerned about her health.

Several days later they learned from their veterinarian that Zoe's symptoms were indicative of hyperthyroidism, even though the cat did not display other typical symptoms, such as vomiting, diarrhea, nervousness, weakness, and lethargy. He then verified the enlargement of her thyroid gland by palpation and confirmed a high thyroid hormone level. Since these clinical signs can be associated with several conditions, the veterinarian ruled out other possible causes before giving a diagnosis of hyperthyroidism.

Outcome: The veterinarian suggested treating the condition with a daily dose of oral Methimazole to minimize the symptoms of the disease, being careful to explain that it was not a cure and that it would be a required treatment for the duration of the cat's life. The medication soon reversed all symptoms. Lethargy and vomiting – possible side effects – were not a problem. Because of the seriousness of hyperthyroidism, Zoe was checked regularly by her veterinarian.

For full details on this medication, download the free patient information sheet.