[Rheumatoid arthritis. Therapeutic efficacy of methotrexate and its hepatotoxic effects]

The efficacy and toxicity (specially hepatic) of methotrexate in low doses (7.5 mg/week) was prospectively assessed in 21 patients with rheumatoid arthritis refractory to treatment with gold or penicillamine, during two years. Three patients were prematurely withdrawn from the protocol. A fast and significant improvement of RA was observed during the first six months, which tapered thereafter. Erythrocyte sedimentation rate decreased from 51.5 +/- 20.1 to 27.7 +/- 11.5 mm/h (p < 0.05). A rise in serum transaminases, always raising to less than twice the normal value, was observed in 75% of patients in some moment of the follow up. Hepatic scintigraphy did not show significant changes. Hepatic histological alterations were mild and no changes were observed after two years of treatment. The main secondary effects were moderate and transitory gastrointestinal and hematological disturbances. The prednisone dose was decreased from 6.8 +/- 2.6 to 4.8 +/- 1.9 mg/day at twelve months. There were no withdrawals due to drug toxicity. It is concluded that methotrexate proved to be efficacious in the treatment of rheumatoid arthritis refractory to conventional treatments. Its secondary effects, although frequent, were discrete and transitory and there were no changes in liver histology.