[Megaloblastic anemia associated with salazosulfapyridine treatment for rheumatoid arthritis].

A 70-year-old man was diagnosed as having rheumatoid arthritis (RA) in 2005. He was treated with 1 g salazosulfapyridine (SASP) daily for two years. Hematological investigations conducted since 2005 demonstrated hemoglobin concentrations of 8 approximately 9 g/dl, which then dropped to 4.9 g/dl on November 21, 2007, following which he was admitted to our hospital. Megaloblastic anemia associated with SASP treatment and anemia of chronic disorders were diagnosed on the basis of folate deficiency and bone marrow examination. This report describes a case of megaloblastic anemia, which developed two years after starting SASP and promptly recovered after its withdrawal and treatment with folic acid and prednisolone. The doses of SASP prescribed for RA in Japan are less than those prescribed abroad. Megaloblastic anemia associated with SASP treatment for RA is not usually detected in Japan. Currently, SASP is widely used and one of the key drugs in the treatment of RA. This case suggests that SASP therapy in RA might result in megaloblastic anemia.