What are the risks associated with radioiodine therapy for feline hyperthyroidism?
The radioiodine treat involves a single injection of a very small volume (<1ml) administered subcutaneously (under the skin). Because the treatment does not require any anesthetic or even extensive manipulation of the patient, the risks are virtually nonexistent. Rarely cats will demonstrate evidence of a sore throat following the treatment. This is more common in cats with large thyroid masses receiving large doses of radioiodine. Recent reports (Survival times for cats with hyperthyroidism treated with iodine 131, methimazole, or both: 167 cases (1996 2003)) reveal that cats treated with radioiodine live approximately twice as long as cats treated with methimazole. So the real risk is associated with not treating a hyperthyroid cat with radioiodine, as chronic medical management reduces the cat's life expectancy by approximately 2 years on average.
