Nephrotic syndrome associated with methimazole therapy.

Thionamide drugs are widely used in the management of hyperthyroidism and are infrequently associated with adverse reactions. We report the development of the nephrotic syndrome during methimazole (Tapazole) therapy in a young man with Graves' disease. His proteinuria remitted promptly with discontinuance of the drug, and renal histologic features bore a striking resemblance to the toxic nephrosis induced in animals by the aminonucleoside of puromycin. In view of the histologic similarities, we propose that methimazole acted as a direct glomerular toxin, inducing the nephrotic syndrome in this patient.