Prolonged Treatment With Antithyroid Drugs: How Long to Treat Safely … Months, Years, or a Lifetime?

Objective: To describe a case where continuous use of antithyroid medications was safely and effectively employed for the treatment of hyperthyroidism over a period of 14 years in a patient who refused radioactive ablative therapy and surgery. Case Report: The patient is a 71-year-old woman who presented with complaints of tachycardia and tremors along with a diffusely enlarged goiter without appreciable nodules. At the time of evaluation, she was clinically and biochemically hyperthyroid. An I123 thyroid uptake and scan revealed a toxic multinodular goiter. She was started on propylthiouracil therapy, which was discontinued due to generalized pruritus. After approximately 4 months of refusing alternative antithyroid therapy, she was started on methimazole. In the subsequent 14 years of management, she relapsed 3 times off antithyroid drugs. However, she never developed any major side effects with the maintenance of methimazole dose of 5 mg daily. Conclusions: The goal of treatment for hyperthyroidism is to render the patient euthyroid safely. However, when treated with radioactive ablative therapy or surgery, the patient is at high risk of being on lifelong thyroxine therapy. Therefore, it appears reasonable that well-informed patients who would prefer lifelong antithyroid therapy, as opposed to lifelong thyroxine therapy, should be given that option.