IODINE-CONTAINING DRUGS AND THYROID-FUNCTION - A DIAGNOSTIC AND THERAPEUTIC CHALLENGE

Iodine-induced thyroid dysfunction will become more important in Austria in the near future, because of the augmentation of the iodine content in salt in 1990. This review therefore tries to summarize the diagnostic and therapeutic problems that may arise in iodine-induced thyroid disease. After discussion of the physiologic reaction of the normal thyroid to iodine the most frequently used iodine-containing drugs used in Austria are presented. Special emphasis is laid on iodine containing antiseptics and on the antiarrhythmic drug amiodar-one. The influence of iodine supplementation on the reaction of diseased thyroid glands to iodine overload is stressed. The diagnosis of iodine induced thyroid dysfunction is relatively simple, once it is thought of. Amiodarone-iodine induced thyroid disease may be an exception, because of the intrinsic effect of this drug on thyroid hormone metabolism. Since high intra-thyroidal iodine content inhibits the action of thyrostatics, therapy of iodine-induced hyperthyroidism may be complicated. Alternative possibilities such as cortisone, perchlorate or surgery in thyroid storm are presented. Substitution with 1-thyroxine in iodine-induced hypothyroidism may be harmful in elderly patients with cardiac problems. In conclusion, this review tries to present the state of the art of the solution of diagnostic and therapeutic problems in thyroid dysfunction due to iodine administration.