Pets Are Important Too

Treatment Options For The Cat With Hyperthyroidism

by Aurore Fontai

Has your veterinarian determined that your feline companion has a thyroid tumor? These are slow-growing tumors, but they do affect how the thyroid controls metabolism. There are three primary treatment options available. Factors such as your budget and lifestyle will help determine the approach that is best for your cat and you. Here are the three ways a cat clinic will treat hyperthyroidism and what you can expect from each.


A medication commonly given to cats for the treatment of a thyroid tumor is methimazole. This is a pill that you give your cat once or twice a day to control the amount of hormones that the thyroid produces. The decreased hormone level reduces your cat's metabolism so they are less active, are not always at the food and water dishes, and can relax without getting up every few minutes.

When starting this medication, your vet will do blood tests on your cat every few weeks and adjust the dosage of the medicine until the thyroid hormone is maintained at the right level. When the proper level is reached, you'll continue giving your cat this medication daily and get a blood test once a year.

Your cat will be on this medication for the rest of their life. The tumor will continue to grow requiring adjustments to the medicine. Your cat will need higher doses to keep their metabolism under control. The initial cost of the medication is low, but if your cat lives with this disease for several years, the accumulative cost of this treatment could be high.


Your vet can remove all or part of the cat's thyroid gland to get rid of the tumor. Your cat will then need to be on thyroid medication  to compensate for the missing gland. They may also need to have a calcium supplement since the thyroid contributes to calcium management in the blood. This is an expensive procedure requiring general anesthesia and a surgical team. If the thyroid gland is not entirely removed, there is a risk that tumor cells will develop in the remaining tissue.

Radiation Therapy

You'll take your cat to a special cat clinic that is set up to work with radiation. Radioactive iodine is injected into your cat's blood and picked up by the thyroid gland. The tumor cells die slowly with only a few of the thyroid cells being affected. The thyroid hormone level returns to normal a few weeks after the treatment. The cost of this procedure is high but is only a one-time cost. The prognosis of permanently removing the tumor cells is good.

Factors to Consider When Making the Choice

Your vet can recommend the best options based on your cat's age and health. For example, radiation therapy may not be an option if your cat also has kidney issues. If all of the options are available, some of the factors to consider include:

  • Can you give your cat a pill once or twice a day?
  • Do you frequently travel? This would require that someone else give your cat their medicine.
  • Can you afford the cost of radiation therapy or surgery?

For more information, contact a cat clinic like the one at Metropolitan Cat Hospital Limited.