How Long Can Cats Be on Tapazole?

Most cats don't experience side effects from thyroid medication.
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If Missy has been diagnosed with a hyperthyroid, you may have decided to treat her with Tapazole. Your vet has probably explained that Tapazole won't cure her thyroid issues, but will keep them in check. Barring unpleasant side effects, she'll probably be on medication for the rest of her life.

How Tapazole Works

Tapazole, which is usually known by its generic name methimazole, is the medication used to treat hyperthyroidism. Depending on your cat's thyroid activity, she'll require 1 to 3 doses daily. The drug can be given in pill form or as a gel that is applied to the hairless inside tip of her ear.

Side Effects of Tapazole

Most cats don't experience side effects from Tapazole, although studies show that about 18 percent of cats do. Common side effects include loss of appetite, lethargy and vomiting. There is potential for some more serious consequences from medication, including facial itching, anemia and kidney damage. If Missy experiences minor side effects, you'll probably be advised to stop giving her medicine until her symptoms clear up. The vet will gradually re-introduce methimazole to her until she is back at her required level.

In most cases, if a cat doesn't display any adverse side effects from medication, she'll be able to stay on it for the long-term.

When to Stop Tapazole

Even the best of cats can be difficult to medicate, so it can be challenging to face giving Missy Tapazole for the rest of her life. Other cats never quite return to their pre-hyperthyroid state and others can develop secondary heart disease. In these cases, if it's financially possible and treatment is accessible, radioactive iodine therapy is a sound option. This method actually cures the condition by "killing" the hyperactive thyroid cells, eliminating the need for any medication in the future.

Sometimes methimazole is given to cats prior to starting radioactive iodine therapy to unmask potential kidney issues. Often, a hyperthyroid will hide declining kidney health. When the thyroid is controlled through medication and Missy's body starts functioning as it normally should, blood tests can reveal how her kidneys are performing. If it turns out she has potential kidney problems, you and your vet will have to determine the best course of action.

Tapazole for Life

If Missy has been on Tapazole for three months and hasn't had any bad reactions to it, chances are she's going to manage the medication well for years to come. Although in the long run, with blood tests and medication refills, methimazole can actually cost more than radioactive iodine therapy, there is a benefit to the flexibility the medication can provide. If she develops other issues, such as with her kidneys, your vet will be able to adjust her medication appropriately.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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