I-131 radioiodine therapy for cats


At Carolina Animal Specialty & Emergency, we do everything possible to extend a pet's quality of life. Our premier I-131 therapy center offers feline therapy to treat hyperthyroidism. This minimally-invasive injection of radioactive iodine can save a cat's life—often in a single treatment.

Healing cats with hyperthyroidism

When a cat is diagnosed with feline hyperthyroidism, it's important to find treatment as quickly as possible. This affliction causes a feline's thyroid to produce hormones T3 and T4 in excess, resulting in tumors and neck swelling. If not treated, the disease can lead to hypertension, high blood pressure, heart disease, organ failure, and—potentially—a shortened life.

Thankfully, hyperthyroidism can often be curable. In fact, the majority of cats who undergo I-131 therapy treatment, which requires no anesthesia or subsequent pain management medications, are cured within a single treatment.

Want to learn more? Get in touch with our hospital. 

Signs of hyperthyroidism in felines 

While cats are notorious for hiding symptoms, the signs of hyperthyroidism can often be blatant. Keep an eye out for:

The most common signs associated with hyperthyroidism are

  • Weight loss, despite a ravenous appetite
  • Hyperactivity
  • Excessive thirst
  • Excessive urination
  • Diarrhea and/or vomiting
  • Heart disease (such as tachycardia or hypertrophic changes)
  • Panting
  • Hypertension
  • Excessive shedding and matting of their fur
  • Palpable thyroid masses

It never hurts to be too careful. If you see any of these signs in your cat, please contact us as soon as possible to determine the next steps. 

Cat on Indoor Tree

Hyperthyroidism treatment options

When you bring or refer a cat to our team at Carolina Animal Specialty & Emergency, we'll create a custom course of action to combat hyperthyroidism. Typically, we'll explore one or a combination of the following options:

I-131 Therapy
Utilizing a special medicine made from radioactive iodine, our hospital is renowned for its treatment against hyperthyroidism. As part of the treatment, the patient will receive the injection and then be carefully monitored for a few days. While there may be slight discomfort or slight hair or pigment loss at the site of the injection, adverse effects are minimal—especially considering that this treatment could save the patient's life!

Thyroid surgery
In some extreme cases, thyroid surgery may be necessary to protect feline patients from hyperthyroidism damage. As goes with most veterinary surgical procedures, thyroid surgery requires anesthesia. Since hyperthyroid patients are at greater risk with anesthesia than typical patients, our qualified team at Carolina Animal Specialty & Emergency will closely monitor the patient before, during, and after the surgery.

Daily oral medication
Methimazole (brand name Tapazole®) is another option to treat feline hyperthyroidism. However, as any cat owner knows, it can be a challenge to administer a daily pill with feline, which can cause stress for both the pet and owner. The treatment doesn't cure the cat's condition but instead manages symptoms to keep the feline comfortable. Beyond the daily medication, this form of treatment requires frequent monitoring and laboratory tests to keep a close eye on the patient's response to treatment.

y/d Diet
Some say that food is medicine, and in the case of hyperthyroidism, a special low-iodine diet can help reduce symptoms in felines. For this diet to be effective, it must be the only food that the cat consumes for the rest of their life, which can be challenging for pet owners to uphold. A y/d diet can also be expensive and may not be a permanent solution for hyperthyroidism relief in your cat.

Ultimately, I-131 radioiodine treatment is the simplest and most non-invasive way to treat hyperthyroidism in cats. Schedule your cat's I-131 radioiodine therapy treatment today

We're here to provide a quick solution to your feline's hyperthyroidism. Please do get in touch for more information.

I-131 treatment details 

Once a referral is received, our veterinarians will review the patient's case in detail. Working hand in hand with the primary veterinarian and owner, we'll evaluate your patient's potential success with this form of treatment.

If the cat is a candidate, we'll conduct a thorough and complete physical exam on the same day of your treatment. Since your cat will stay with us for a few days after receiving I-131 therapy, you're welcome to bring food from home to keep your cat comfortable during the stay.

Kitten on Blanket

Notes for referring veterinarians

Please consider the following when referring a patient to our hospital:

  • Radioactive iodine therapy can only be provided to medically stable cats
  • If on methimazole, a cat must discontinue their medication three days prior to the treatment
  • When referring, we require the following diagnostic test (via fax or mail) 7-30 days prior to the treatment:
    • Physical exam
    • Complete blood count
    • Urinalysis
    • Serum biochemistry panel
    • Resting T4 level
    • Chest radiographs
    • Cardiac ultrasound (highly recommended)

Referring veterinarians: Please contact our hospital or use the online form. Thank you for your referral.

How to schedule feline hyperthyroidism treatment with our hospital

Please have your veterinarian call to arrange the referral of your pet to our I-131 service. We can schedule a consultation with one of our experts to assess your pet's case. 

For new clients

  1. Have your veterinarian schedule a consultation for your pet
  2. Your pet will be assessed in consultation with our I-131 expert
  3. The veterinary will discuss a treatment and diagnostic plan
  4. You’ll be given an estimate for treatment
  5. We provide care to restore your pet’s health

For referring veterinarians

Please contact our hospital or fill in the online form for the patient in need of a I-131 consultation. Thank you for your referral.