Hyperthyroidism + I-131 Treatment

Faithful Friends Veterinary Clinic & Cat Specialty Center now offers on-site radioactive iodine (I-131) therapy, the most effective and preferred treatment for feline hyperthyroidism.

What Is Feline Hyperthyroidism?

Hyperthyroidism is the most common endocrine disease in older cats. It occurs when the thyroid gland produces too much thyroid hormone (T4), which can cause:

  • Weight loss despite a good appetite
  • Increased thirst and urination
  • Restlessness or hyperactivity
  • Vomiting or diarrhea
  • Elevated heart rate and blood pressure

If left untreated, hyperthyroidism can damage the heart, kidneys, and overall quality of life.

Radioactive Iodine (I-131) is widely considered the long-term treatment of choice for cats with hyperthyroidism. This non-invasive procedure offers a potential permanent cure, eliminating the need for daily medication and routine bloodwork.

How It Works

The treatment involves a single injection of radioactive iodine. Overactive thyroid tissue absorbs the iodine, and the radiation destroys the abnormal cells—while leaving normal thyroid tissue unaffected. Most cats return to a normal thyroid state within 2–4 months following treatment.

Why Choose I-131 Treatment

Advantages

>95% cure rate in most cases

No surgery and no long-term medications required

Most successful treatment for thyroid carcinoma

Rare serious side effects

Preferred standard of care in human medicine

Considerations

Higher upfront cost

Requires a licensed facility and trained professionals

2–4-day hospital stay required

Small risk (<5%) of developing hypothyroidism, usually manageable

Post-treatment radiation safety guidelines must be followed at home for a short time

Eligibility for I-131

Before your cat can be approved for I-131, a methimazole trial is required. This ensures your cat’s kidney function remains stable while thyroid hormones are medically controlled.

Required Labs:

  • Complete Blood Count (CBC)
  • Comprehensive Biochemistry Profile with Electrolytes
  • Total T4
  • Urinalysis

These labs must be completed within four weeks prior to I-131 treatment. Cats must be otherwise stable and not have uncontrolled medical conditions.

What Makes Our Treatment Experience Unique?

Faithful Friends Veterinary Clinic is one of the few veterinary facilities in Columbus equipped and licensed to perform this advanced therapy. Treatment includes a hospital stay of 2–4 days, followed by at-home care guidelines for your cat’s safety and peace of mind.

At The Cat Specialty Center at Faithful Friends, we provide an elevated experience built with your cat in mind:

  • Gold Level Cat Friendly Practice®
  • Radiation ward designed for comfort, safety, and enrichment
  • Spacious double kennels with shelves, sleeping, and toileting areas
  • 24/7 live camera access so you can check on your cat anytime
  • Cat-approved entertainment: bird watching or fish tank movies 🎥
  • Medications administered safely by our feline-certified technicians

Aftercare: What to Expect When Your Cat Comes Home

Although radiation levels are low at discharge, we follow strict guidelines to protect you and your family:

For 3 Weeks After Treatment:

  • No contact with infants, pregnant women, or nursing mothers
  • Limit snuggling and sleeping near your cat
  • Children should remain 6+ feet away
  • Wash hands after contact with your cat or cleaning the litter box

Litter Box Protocol:

  • Wear rubber gloves for 30 days when handling waste
  • All waste must go into a designated “hot trash” bag
  • Do not dispose of this bag until 90 days post-treatment
  • Keep stored waste in a garage, basement, or outdoor location
  • Gloves and soiled items also go into this designated bag
  • Do not discard early – waste facilities may detect radiation, which can lead to investigation and fines

Trusted Care from Ohio’s Only Board-Certified Feline Specialist

All I-131 treatments are overseen by Dr. Ashlie Saffire, DABVP (Feline)—the only actively practicing board-certified feline specialist in Ohio. With expertise in feline-specific medicine, advanced diagnostics, and fear-free handling, Dr. Saffire leads our Cat Specialty Center with compassion and credibility.

Ready to Learn More?

If your cat has been diagnosed with hyperthyroidism, contact our team to schedule an eligibility consultation or learn more about the I-131 process.
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