Methimazole-Induced Severe Aplastic Anemia: Unsuccessful Treatment with Recombinant Human Granulocyte-Monocyte Colony-Stimulating Factor

Aplastic anemia is a rare but severe complication of thionamide therapy. Although colony-stimulating factors have been used extensively in thionamide-induced agranulocytosis with good results, the same might not apply to aplastic anemia. We present a case of a patient with methimazole-induced aplastic anemia in which, as administration of recombinant human granulocyte—monocyte colony-stimulating factor for a week did not result in an increase in peripheral blood cell count, standard immunosuppressive treatment was needed to restore normal hematopoiesis. The clinical characteristics of this patient are compared with those of previous cases of thionamide-induced aplastic anemia, especially with the only other reported patient in which colony-stimulating factors were used.