[Issues of side effects induced by antithyroid drugs].

Antithyroid drugs have been widely used in the treatment of hyperthyroidism. However, these drugs are known to have significant side effects. There are minor side effects such as skin rash or urticaria and major side effects. Especially, agranulocytosis and MPO-ANCA related vasculitis syndrome are the most serious, and although it occurs infrequently, it is clinically important, and clinicians must be alert to it when using antithyroid arugs. The author describes about the issues of side effects induced by antithyroid drugs.