Response to adjuvant therapy with potassium perchlorate in amiodarone-induced thyrotoxicosis: observations on three cases

Amiodarone-induced thyrotoxicosis (AIT) is a common clinical disorder that may be life threatening and whose clinical manifestations and response to treatment may vary among patients. We present three patients treated with amiodarone for atrial fibrillation who developed AIT at least 36 months after beginning the treatment. Thyrotoxicosis worsened the underlying cardiac disorders and was resistant to treatment based on the combination of dexamethasone 8-12 mg/day i.v., thioamides 45 mg/day p.o., beta blockers and potassium perchlorate at doses of 800 to 1000 mg per day p.o. Two of the patients attained sustained euthyroidism after 12 and 32 days of combined treatment, while the third required total thyroidectomy. The combination of thioamides with potassium perchlorate is an appropriate form of therapy for AIT in patients resistant to thioamides. The use of this combination should be evaluated in patients with mixed AIT or AIT of unclear etiology.