July - September 2007, Volume 3, Issue 3

Cho SR, Seaquist ER

Amiodarone-induced thyrotoxicosis following treatment for amodarone-induced hypothyroidism

Acta Endo (Buc) 2007, 3 (3): 359-367
doi: 10.4183/aeb.2007.359

Amiodarone-induced thyroid dysfunction is common but the development of hyperthyroidism following treatment for amiodarone-induced hypothyroidism is very unusual. We recently saw an elderly man who developed severe thyrotoxicosis four years after diagnosis of and initiation of treatment for amiodarone-induced hypothyroidism. The thyrotoxicosis was treated first with methimazole and discontinuation of L-thyroxine replacement and then with methimazole and prednisone. After successful treatment and withdrawal of therapy, he subsequently re-developed hypothyroidism and required resumption of L-thyroxine replacement. This case highlights that amiodarone-induced hyperthyroidism can occur in patients who previously became hypothyroid on the drug.

Keywords: amiodarone-induced hyperthyroidism, amiodarone-induced hypothyroidism, iodine

Correspondence: Professor Elizabeth R. Seaquist MD, Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota Medical School, MMC101, 420 Delaware St SE, Minneapolis, MN 55455, Phone: 612 626 1960, Fax: 612 626 3133, e-mail: seaqu001@umn.edu