[Pancytopenia and Pneumocystis carinii pneumonia associated with low dose methotrexate pulse therapy for rheumatoid arthritis--case report and review of literature].

Low-dose weekly pulse MTX therapy is effective for rheumatoid arthritis (RA) and is used for patients with RA who are unresponsive to conventional disease-modifying antirheumatic drugs (DMARDs). We used MTX to a 62-year-old man with RA who had received DMARDs for 5 years. MTX was effective for RA but after 12 weeks MTX therapy started, he complicated pancytopenia and developed Pneumocystis carinii pneumonia. We reviewed all RA patients reported in Japan and in the world from 1965, complicated with Pancytopenia (37 cases) and Pneumocystis carinii pneumonia (13 cases) after MTX therapy. Results were as following; (1) MTX should not be used with TMP-SMX. and risk factors for pancytopenia were (2) age over 60 years old (3) renal hypofunction (4) use of NSAID.