Intra-articular drug therapy in rheumatoid arthritis. A study with indoprofen

Six patients (4 men, 2 women) with moderate/large knee effusions due to rheumatoid arthritis (RA) were studied after receiving indoprofen, 25 mg intra-articularly and then 200 mg orally 1 week later. There was significant improvement in pain (t = 3.74, P less than 0.05), morning stiffness (t = 2.91, P less than 0.05) and range of movement (t = 2.52, P less than 0.05) for at least 1 week following the intra-articular injection. The terminal phase plasma half-life after the 200 mg oral dose was 6.4 +/- 0.7 h (mean +/- SEM) and was significantly longer than the often quoted plasma half-life of 2-3 h from previous studies, but much less than the pharmacodynamic half-life. Synovial fluid concentration were not significantly different from those in plasma in the post-distribution phase. Intra-articular indoprofen may be a useful addition to the treatment of RA.