The effect of amiodarone on the control of hyperthyroidism by propylthiouracil

We studied the efficacy of amiodarone (800, 600, 400 and 200 mg orally daily during weeks 1, 2, 3 and 4, respectively) plus propylthiouracil (PTU, 100 mg orally every 8 h) in comparison to PTU alone in the early treatment (28 days) of Graves' disease patients. Circulating T3 and T4 decreased earlier and more markedly in the amiodarone plus PTU-treated group. An initial rise of circulating rT3 above the base-line value followed by a gradual decline was observed in the former group while only a decline below the base-line values was observed in the latter group. The resting pulse rate decreased and body weight increased significantly in the amiodarone plus PTU-treated group. In the PTU-treated group, significant weight gain was observed later in the course of treatment while no significant reduction in pulse rate was observed. No major side-effects of amiodarone were observed during the course of treatment. This study suggested that the combination of amiodarone and PTU was more efficacious than PTU alone in reducing circulating T3, T4 and clinical hyperthyroidism early in the course of treatment of patients with Graves' disease. This regimen has an additional potential advantage because of the antiarrhythmic property of amiodarone, especially in situations when a beta-blocker is contraindicated.