Plasma and synovial fluid pharmacokinetics and prostaglandin inhibitory effect of indoprofen in patients with rheumatoid arthritis.

Indoprofen was given intravenously (bolus followed by infusion) and orally to 7 patients suffering from active rheumatoid arthritis with knee joint effusion. Indoprofen readily penetrated into synovial fluid in amounts which were directly correlated with areas under curves of plasma drug levels. Synovial fluid acted as a compartment distinct from the central (plasma) compartment. Indoprofen caused a substantial decrease in E2 and F2 alpha prostaglandin concentration in synovial fluid.