Tiopronine-induced polymyositis

BACKGROUND: D-penicillamine-induced muscle disorders are well-known, tiopro nine-induced disorders are less often reported. CASE REPORT: A 62-year-old patient, given tiopronine for rheumatoid arthrit is, developed severe polymyositis with characteristic clinical and patholog y features. The course was favorable after tiopronine withdrawal and substi tution with methotrexate. DISCUSSION: Clinicians should be aware of the side-effects of tiopronine, p articularly muscle disorders, and implement careful surveillance to achieve early diagnosis and appropriate therapy.