[Generalities on clinical trials of the effectiveness of non-steroidal anti-inflammatory agents].

Non-steroidal antiinflammatory drugs represent a strictly symptomatic treatment since they act mainly on pain and act fast. One week cross-over study models confirm the intrinsic pharmacodynamic effect of the test product, specify daily doses and optimal dosage regimens and enable comparison of the product with a reference drug. These studies must be conducted in out-patients, by an experienced investigator, using a double-blind design in a sufficiently large number of patients. Rheumatoid arthritis, ankylosing spondylitis and osteoarthritis of the hip and knee are the most suitable models for such studies. A long-term efficacy study is best done by analyzing the rate of withdrawals from treatment as a function of time.