Radioactive Iodine Therapy (I-131)

Radioactive Iodine Therapy The Gold-Standard Treatment for Feline Hyperthyroidism

A Safe, Effective, One-Time Treatment for Hyperthyroidism in Cats

Radioactive Iodine Therapy (I-131) is widely considered the gold-standard treatment for feline hyperthyroidism. In most cases, it offers a permanent cure with a single injection, eliminating the need for lifelong medication or invasive surgery.

At White Haven Veterinary Hospital, our specially trained medical team and dedicated treatment facilities allow us to safely and effectively provide this advanced therapy for eligible cats.

What Is Radioactive Iodine Therapy (I-31)?

Radioactive Iodine Therapy uses a carefully controlled dose of radioactive iodine to selectively target and destroy overactive thyroid tissue while leaving healthy tissue unharmed.

Because the thyroid gland naturally absorbs iodine, the treatment is exceptionally precise. Once the abnormal tissue is eliminated, normal thyroid function can gradually return over the following weeks. This treatment does not require surgery and is performed with minimal stress for your cat.

How I-131 Treatment Works

The Treatment Process:

This targeted approach allows for effective treatment without anesthesia or surgical risk.

Why Radioactive Iodine Therapy Is the Preferred Treatment

Radioactive Iodine Therapy offers several significant advantages over other treatment options:

✔ High Success Rate

✔ One-Time Treatment

✔ No Surgery or Anesthesia

✔ Spares Healthy Tissue

✔ Long-Term Health Benefits

What Condition Does I-131 Treat?

Radioactive Iodine Therapy is used to treat feline hyperthyroidism, a common hormonal disorder in older cats.

Hyperthyroidism occurs when the thyroid gland produces excessive thyroid hormone, leading to an abnormally high metabolic rate. Without treatment, this condition can place serious strain on the heart, kidneys, and other organs.

Common Signs of Feline Hyperthyroidism

Cats with hyperthyroidism may show one or more of the following signs:

Without treatment, hyperthyroidism can become life-threatening.

What to Expect During I-131 Treatment

Hospital Stay (Required by Law)

For safety and radiation protocols, treated cats must remain hospitalized for five days.

During this time: Our trained team provides all daily care, Cats are monitored closely, & Owners cannot visit due to radiation regulations.

At-Home Aftercare

After discharge, a few important precautions are needed:

For 3 months after treatment:

While this may sound strict, these protocols protect everyone at home and are far easier than lifelong medication.

After Treatment: What Happens Next?

Most cats show improvement quickly, with full thyroid regulation returning within 1–3 months.

Once stabilized, symptoms such as weight loss, rapid heart rate, and restlessness typically resolve—allowing your cat to enjoy a healthier, more comfortable life.

Is Your Cat a Candidate for (I-131) Therapy?

Before diagnosing hyperthyroidism or determining whether a cat is eligible for Radioactive Iodine (I-131) Therapy, comprehensive diagnostic testing is required to evaluate thyroid function and overall health.

White Haven Veterinary Hospital is proud to offer Radioactive Iodine (I-131) Therapy as a specialty service, and we frequently work with referring veterinarians and hospitals to provide this advanced treatment for their feline patients.

Whether your cat has already been diagnosed by your primary care veterinarian or we are exploring treatment options for your feline companion, our team is here to guide you through the process.

Pre-Treatment Requirements

To ensure safety and the best possible outcome, the following diagnostics are required prior to scheduling I-131 treatment:

These requirements allow us to confirm eligibility and coordinate care appropriately—especially for patients referred from other veterinary hospitals.

For pet owners who are not current clients of White Haven Vet, we are happy to communicate directly with your primary care veterinarian to obtain records and testing. For referring veterinarians, we welcome collaboration and provide clear referral guidelines to ensure a seamless process.

To learn more about our diagnostic process please visit our Veterinary Diagnostics page. To learn more about our referral process, please email our team at wvinfo@whitehavenvet.com, and someone will be in touch right away.

If you have questions or would like help determining whether your cat is a candidate for I-131 therapy, our team is happy to assist. Click here to request an appointment today.