Methotrexate in rheumatoid arthritis.

A variety of disease-modifying antirheumatic drugs (DMARDs) are available to control the clinical activity of rheumatoid arthritis (RA). Methotrexate (MTX), an analogue of folic acid and of aminopterin, is the most commonly used DMARD and is now prescribed worldwide to at least 500,000 patients with RA. The mechanism by which MTX used at a low dose modulates inflammation in RA is still unknown. Monitoring of the therapy in terms of MTX concentration in patients with RA seems not to have a significant influence on the effectiveness of the treatment. Two meta-analyses showed that MTX has one of the best efficacy/toxicity ratios. It should be the first DMARD used in the majority of patients with RA at this time. However, a significant number of patients treated only with MTX fail to achieve optimal disease control, so there are many combinations of DMARD regimes. It is hoped that more aggressive use of conventional DMARDs and biological agents will result in less disability and a higher proportion of patients achieving remission. The therapy of RA is a dynamic process and requires maintaining a delicate balance between benefits and risks. Even with the newer biological agents, MTX continues to serve as a reference point and there is still a role for MTX in the treatment of RA patients.