Psoriatic arthritis: clinical response and side effects to methotrexate therapy.

In the last decade, methotrexate (MTX) has emerged as a useful second line agent for a variety of arthritides. However, there still exists some reluctance for its wider use mainly because of concerns about its liver side effects. We describe our clinical experience with this drug in psoriatic arthritis (PsA). The study group included 24 men and 16 women, with a mean age of 47 years (16-75), with oligoarticular (13) or polyarticular (27) involvement, with a mean disease duration of 12 years (1-36). Patients received a mean dose of 11.2 mg of MTX orally/week during a mean period of 34 months (6-132). Seven had been previously treated with other second line agents. Thirty-eight patients had an excellent or good response. In them, the erythrocyte sedimentation rate dropped in a mean of 38 mm/h. Only 2 patients had a rather poor response. Two patients discontinued the medication because of side effects: leukopenia in one and stomatitis in the other. Eleven patients presented with liver test abnormalities: 3 mild, 6 moderate and 2 severe. Seven patients had 11 liver biopsies. Except for one, none had evidence of cirrhosis or inflammation. Indeed, no changes were observed in the histopathology in those with repeated biopsies. The case reported as cirrhosis occurred very early in the course of MTX therapy. He continued taking MTX treatment without further deterioration of liver chemistry and/or histology. It is concluded that MTX is an effective and safe agent in PsA. Results also indicate that it is not necessary to perform liver biopsies on a routine basis.