HAS THE USE OF ANTITHYROID DRUGS FOR GRAVES-DISEASE BECOME OBSOLETE

In spite of an experience of almost 50 years of use of antithyroid dru gs and radioiodine for the treatment of Graves' disease, the rationale for choice is often obscure. Early reports of high remission rates du ring thiourea therapy were followed by less optimistic ones, which alo ng with other factors may have fueled the current major shift toward u se of radioiodine. This review examines whether or not the use of anti thyroid drugs indeed may have become obsolete. The intrathyroidal and extrathyroidal mechanisms of action of the drugs are reviewed with emp hasis on their potential immunosuppressive effects. The latter may inv olve a direct effect on thyroid follicular cells, a direct suppression of TSH receptor antibody formation, or indirect effects mediated via heat shock proteins, oxygen free radicals, and the immune system. Pote ntial factors associated with success or failure with antithyroid drug therapy are discussed, such as the effects of dose and duration of tr eatment, iodine milieu, and concomitant L-thyroxine therapy. The risks inherent to radioiodine therapy are only briefly described with empha sis on the possible aggravation by radioiodine of preexistent ophthalm opathy. The reader must decide whether the evidence marshalled convinc ingly indicates that the use of the thiourea compounds should be aband oned. The author thinks not, and is optimistic that imminent discovery of the yet elusive and enigmatic pathogenesis of Graves' disease will permit new and innovative treatment or more effective use of currentl y available therapies.