Methotrexate in rheumatoid arthritis: an update.

Methotrexate, a folic acid antagonist, is being employed more frequently in an attempt to control rheumatoid arthritis that has not responded adequately to conventional therapies. Systemic administration of 7.5-15 mg weekly in a pulse fashion appears to be effective without precipitating serious adverse effects. Concern over potentially serious adverse effects and lack of well-controlled clinical trials have limited its use to severe, refractory disease. Its use in the future is likely to increase in these patients because of its ease of administration and the high response rate noted in clinical studies.