Knee rheumatoid synovitis (KRS) successfully treated with intra-articular rifamycin SV (Abstract)
The effects of intra-articular rifamycin SV on rheumatoid synovitis were evaluated in two studies, open and double-blind versus saline solution. All together, 35 patients were treated with 250–500mg weekly (maximum 10 weeks). Synovial fluid analysis (SFA), clinical activity assessment (CA) and needle biopsy (NB) were performed before, during (SFA and CA) and after (NB) treatment; the latter at various time periods (1–28 months). 34 out of 35 patients experienced a complete disappearance of effusions and marked clinical improvement (lowering of pain and morning stiffness of 55–65%). Only 1 of 10 patients treated with saline solution showed disappearance of effusion and amelioration of clinical condition. The side effects consisted of painful local reaction (20%). In 4 patients (11%) reactions were accompanied by increase of synovial fluid and temperature lose to 38 °C; these reactions subsided within 12–24 h after infiltration. A direct correlation (p<0.01) was found between number of infiltration and the activity grade of synovitis. Synovial membrane showed a reduction of cellular infiltrate and an increase of newly formed connective tissue. Some experimental studies in progress suggest that rifamycin exerts an anti-mitotic effect on synovial membrane and an inhibitory action on synthesis of inflammatory mediators.