[Hyperthyroidism induced by amiodarone]

The incidence of amiodarone-induced thyrotoxicosis remains unclear, partly due to the difficulties encountered in making a firm diagnosis based on thyroid hormone levels. Amiodarone is known to inhibit thyroxine (T4) metabolism, thus bringing plasma T4 concentrations up to levels that may simulate T4 toxicosis. On the other hand, the iodine overload due to the drug itself may create true hyperthyroidism. The purpose of this paper is to suggest practical means of detecting thyrotoxicosis in patients on amiodarone and to discuss the treatment of this side-effect.