Pericarditis: a rare complication of methotrexate therapy.

Serositis is a rare complication of methotrexate (MTX) administration. We report a 60-year-old man with rheumatoid arthritis who developed pericarditis after taking his weekly MTX dose, which recurred within hours after 2 subsequent weekly MTX doses. Pericarditis has not recurred after discontinuance of MTX over 3 years ago. We conclude that he had MTX-induced pericarditis, based on the close temporal relationship between MTX ingestion and manifestations of pericarditis on three distinct occasions because of the previous reports of MTX-induced pericarditis and because pericarditis has not recurred after MTX withdrawal.