The mechanism of action of nonsteroidal antiinflammatory drugs.

Several nonsteroidal antiinflammatory drugs (NSAID), although not all, inhibit proteoglycan synthesis by normal articular cartilage in vitro; the inhibitory effect is much more marked in osteoarthritic cartilage. For salicylates, in vivo data support the in vitro findings; degeneration of articular cartilage in animal models is accelerated by oral administration of aspirin. While it has been suggested that NSAID may be "chondroprotective," no clinical studies exist to support the view that NSAID favorably influence progression of joint degeneration in man, nor do well designed controlled studies show that NSAID are superior to a pure analgesic, e.g., acetaminophen, in treatment of symptoms of osteoarthritis.