41 - Thyroid hormones, iodine, and antithyroid drugs

Abstract

This review of the 2010 publications on adverse reactions to thyroid hormones, iodine, and antithyroid drugs covers levothyroxine, the thyroid hormone analogue eprotirome, iodine and radioactive iodine, and thionamide antithyroid drugs. Hypothyroidism is associated with adverse effects on lipid profiles which are improved by thyroid hormone replacement, and a novel thyromimetic drug, eprotirome, appears to have promising lipid-lowering effects. Radioactive iodine compounds are used in the treatment of benign and malignant thyroid diseases and increasingly in the management of other tumors. The use of diuretics to accelerate elimination of unbound iodine compounds should be undertaken cautiously. Antithyroid drugs, carbimazole (methimazole) and propylthiouracil are widely used in the treatment of hyperthyroidism. Significant adverse reactions include drug-induced agranulocytosis, the management of which is supportive with broad-spectrum antibiotics and colony-stimulating factors. In view of reports of fulminant liver failure, propylthiouracil is no longer recommended as a first-line treatment, except in the first trimester of pregnancy, when carbimazole is relatively contraindicated in view of potential teratogenicity. Other adverse reactions to antithyroid drugs include vasculitis and various skin conditions.