Methotrexate for treating rheumatoid arthritis.

Methotrexate is a folic acid antagonist widely used for the treatment of neoplastic disorders. Methotrexate inhibits the synthesis of deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and proteins by binding to dihydrofolate reductase. Currently, methotrexate is among the most commonly used drugs for the treatment of rheumatoid arthritis (RA). This is an update of the previous Cochrane systematic review published in 1997.