Ipodate therapy in patients with severe destruction-induced thyrotoxicosis.

We describe 4 patients with severe destruction-induced thyrotoxicosis who had a rapid clinical response to oral sodium ipodate (500 mg daily). The underlying thyroid disorders in the patients were postpartum thyroiditis, subacute thyroiditis, silent thyroiditis, and radiation-induced thyroiditis. Ipodate therapy was given for 6 to 10 weeks until restoration of thyroid function to normal. In all patients, an almost complete resolution of symptoms occurred by the third day of ipodate treatment. In the patient with radiation thyroiditis, a daily clinical score of thyrotoxicosis declined within 2 to 3 days. The score remained low as long as the patient was receiving ipodate, but 2 attempts to discontinue ipodate therapy while thyroxine levels were elevated resulted in a rise of the thyrotoxicosis clinical score. This suggests that ipodate therapy, by rapidly reducing triiodothyronine levels through inhibition of the 5' monodeiodination and blockage of the peripheral effects of thyroid hormone, controls severe thyrotoxicosis mediated by destruction and should be considered in this setting in conjunction with beta-adrenergic blockade.