[New NSAIDS: COX-1, COX-2, what about them?].

Non steroidal antiinflammatory (NSAID) drugs are the most widely prescribed drugs against pain and inflammation. Problems of tolerance, particularly gastrointestinal toxicity, limit their use. The central mechanism of NSAID action is the reduction of prostaglandin production from arachidonic acid through cyclooxygenase inhibition. Although such a mechanism was already described 25 years ago, the recent discovery of two isoforms of cyclooxygenase, the cyclooxygenase 1 (COX-1) constitutively expressed in most tissues and the cyclooxygenase 2 (COX-2), inducible, has prompted research in developing new NSAID that would be safer whilst maintaining their efficacy. Nevertheless, their long term efficacy and safety need to be demonstrated in clinical practice. There are still unsolved questions, especially about the physiological role of COX-2.