Thyroid hormones, iodine and antithyroid drugs

Abstract

This chapter discusses thyroid hormones, iodine and antithyroid drugs. Osteoporosis Thyroid hormones directly stimulate bone remodeling with an increased bone resorption, an adaptive increase in bone formation and secondary adaptation in serum calciotropic hormones. In the absence of the bone-resorbing effects of thyroid hormones a mild secondary hyperparathyroidism, increased production of the active 1, 25-dihydroxyvitamin D hormone, and increased intestinal calcium absorption is observed, with the opposite effects in the presence of hyperthyroidism. No new side effects of antithyroid drugs have been reported. Hematological side effects (especially leukopenia and agranulocytosis) are the most feared complications, but such effects are usually reversible. Hepatic toxicity, due to propylthiouracil, carbimazole or benzylthiouracil is occasionally reported and considered to be an allergic idiosyncrasy; it is usually reversible, but occasionally lethal.