Low-dose penicillamine treatment of RA. Comparison of 600 mg and 300 mg regimens

Results and side effects were compared in 100 patients with rheumatoid arthritis treated with 600 mg penicillamine daily and 100 patients given 300 mg daily. While haemoglobin rose and erythrocyte sedimentation rate dropped in both the 300 mg and the 600 mg cohort, no significant improvement in clinical measure could be demonstrated for the low-dose patients. Medication was discontinued because of side effects in 30 patients on the low dose and 41 patients on the higher dose. Only 8 renal complications were seen among the low-dose patients, vs. 26 in the 600 mg cohort. However, 6 patients on the low dose vs. none on the higher dose dropped out because of inadequate therapeutic effect. Further downward adjustment of currently used daily dose, though desirable because of the relationship between dosage and side effects, seems doomed by unacceptable loss of therapeutic efficacy in most cases.