Feline Hyperthyroid Treatment (I-131)

FAQs About I-131 Therapy for Hyperthyroid Cats

• How does hyperthyroidism affect cats?

  Older cats commonly suffer from the endocrine disease hyperthyroidism, which triggers an increased metabolic rate. In turn, this causes a variety of symptoms including vomiting, diarrhea, weight loss, increased blood pressure, rapid or irregular heart rate, or other issues. 

• What are the treatment options for hyperthyroidism?

  The three primary options for treatment of hyperthyroidism include medical therapy with Tapazole (methimazole), surgical removal of the affected thyroid gland, or radioiodine therapy. 

  Surgery may have complications including anesthetic risks and damage to the parathyroid gland primarily, in addition to a risk of recurrence. 

  Tapazole therapy can cause skin rash, vomiting, and problems with bone marrow and liver. 

  Along with daily pilling, it's essential to monitor blood work closely with Tapazole therapy. This can mean annual costs. 

  In rare cases (<5%), some cats may require a second treatment or develop hypothyroidism (under-active thyroid gland) that requires daily thyroid hormone supplementation.

• Why does my cat have to remain hospitalized for so long after treatment?

  Because the radioactive material remains in the cat’s body and is excreted primarily through the urine and feces, your cat is required to remain in our facility until his/her levels are considered low enough for discharge.

  The standard hospital stay is about 5 days, though some cases may require an extended stay. While hospitalized, your cat will be monitored daily by a trained staff member as well as a veterinarian. Medications will be administered as needed, and we encourage you to bring a week’s supply of your cat’s favorite food.

  Unfortunately, no personal effects can be returned so we suggest not leaving any cat toys or bedding (we will provide these).

  Also, we cannot allow visitation until your cat is ready for discharge, but we will give you daily progress reports on your cat.

• What is required following discharge from the hospital?

  For two weeks following discharge, we request that you follow some sensible safety measures while any remaining radiation is excreted from your cat’s body.

  You will receive detailed written instructions that include limiting extensive contact (especially with children or pregnant women), washing hands after handling your cat or his/her litter box, and disposing of litter box waste. Your cat will also need to remain indoors during that time.

• Will my cat experience radiation sickness?

  The treatment is given via a subcutaneous injection, similar to a vaccination. They do not experience radiation sickness. Radioactive iodine is a very safe and effective treatment and is used frequently in human medicine.

• How do I schedule an appointment for I-131 for my cat?

  Please talk with your veterinarian about your cat’s case and whether he or she is an appropriate candidate for I-131. Barton Heights Veterinary Hospital is a referral-based hospital, which means we work closely with your veterinarian to provide the best possible care for your cat. We prefer a referral from your veterinarian before we see your cat for evaluation or treatment.