Pharmacokinetics and biochemical effects in responders and non-responders to non-steroidal anti-inflammatory drugs.

It is now accepted that some patients will fail to respond clinically to one non-steroidal anti-inflammatory drug but will respond to another apparently similar compound (8). There are a number of possible reasons for this failure to respond such as the use of inadequate dosage or inappropriate drugs. However these reasons are unlikely to be applicable in the situation outlined above and we have been interested in exploring further, possible reasons for this failure to respond. We have therefore conducted two studies in patients with rheumatoid arthritis to examine the relationship between the pharmacokinetics of the drugs used, the clinical response to the drug, and certain biochemical effects of the drugs. The initial study with indometha-cin was reported more fully in 1979 (3) and the second study was reported more briefly in 1980 (II). This report reviews the initial study and reports on some new data in the second study.