Rifampin therapy in rheumatoid arthritis.

Several second-line antirheumatic agents possess both immunosuppressive and antimicrobial properties. Rifampin is an antimicrobial agent recently found to exhibit immunosuppressive activity in both animal and human studies. Intraarticular rifamycin SV, a rifampin derivative, has been reported to cause dramatic improvement in gonarthritis in 15 patients with rheumatoid arthritis (RA). These reports along with the personal observation of spontaneous improvement of arthritic symptoms in 2 patients with RA treated with rifampin at our institution, prompted us to conduct a pilot study using oral rifampin at 600-1200 mg daily in 8 patients with active, adult onset, seropositive RA. Although, no clinically important or statistically significant improvement occurred in any of the outcome variables measured (p greater than 0.12), the power of this study to detect such differences was limited. Alkaline phosphatase increased modestly in 7 patients. One patient developed an acute, drug induced, flu-like syndrome with marked elevation of liver enzymes which resolved promptly with drug withdrawal. We conclude that the potential effectiveness of oral rifampin therapy in RA is doubtful.