Effect of a nonsteroidal antiinflammatory drug on synovial fluid in osteoarthritis.
The use of nonsteroidal antiinflammatory drug (NSAID) therapy in osteoarthritis (OA) is controversial because of suggestions that pure analgesics can be as effective as NSAID for pain relief. In addition, there is incomplete information whether antiinflammatory effects have any longterm benefit in OA. NSAID have been known to affect synovial fluid (SF) prostaglandins in rheumatoid arthritis. We describe the first examination of the effect of an NSAID, etodolac, on SF prostaglandins, cytokines, and cells in OA. Joint fluids were studied before and 2 weeks after initiation of therapy with etodolac 400 mg tid. Leukocyte counts, prostaglandin, interleukin 6, and tumor necrosis factor were measured. Pretreatment features of SF did not predict clinical response. We found no change in the relatively low leukocyte counts. However, SF prostaglandin levels and interleukin 6 levels were significantly decreased and tumor necrosis factor alpha levels were increased after therapy with NSAID. This NSAID had potentially important local effects that could be either beneficial or deleterious. Further studies on effects of this and other NSAID on a broader variety of SF and synovial cytokines may help predict longterm effects of NSAID on progression of OA.