Low-dose D-penicillamine therapy in rheumatoid arthritis. A controlled, double-blind clinical trial.

Two hundred twenty-five patients with active severe rheumatoid arthritis were admitted to a multiclinic, controlled, double-blind trial comparing the use of 500 mg D-penicillamine per day, 125 mg D-penicillamine per day, and placebo. One hundred seventy-one patients completed at least 30 weeks of therapy. The 500 mg D-penicillamine group demonstrated statistically significant improvement over the placebo group in grip strength, average circumference of swollen proximal interphalangeal joints, and patient assessment. While the trend was for greater improvement with the larger dose of D-penicillamine, there was no statistically significant difference among the 3 groups in duration of morning stiffness, walking time, physician's assessment, number of swollen joints, or scores for tender and swollen joints. The slight increase in efficacy of higher dose D-penicillamine was associated with increased toxicity.