Rifamycin SV in local treatment of synovitis--a clinical, arthroscopic and pharmacologic evaluation.

Intraarticular injections of rifamycin SV were repeated weekly in patients with rheumatic disease with a chronic knee joint effusion. The clinical signs of synovitis were reduced in all, but disappeared in only one. A post injection reaction with transient local pain and effusion appeared at the third or a later injection in all the patients prompting withdrawal of 3. At these later injections local drug retention was shown by parallel determinations of rifamycin SV in synovial fluid and serum. The post treatment synovial fibrosis seen at arthroscopy could possibly explain the drug retention and the post injection inflammatory reaction. Thus, local treatment with rifamycin SV alleviated but rarely abolished synovitis.