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COX-3: specific for pain and temperature effects?: Cyclo-oxygenases (COX) are present in various forms and are responsible for different physiological and pathophysiological effects. COX-1 is important in the generation of prostaglandins and thromboxanes, and inhibition has analgesic, antipyretic, anti-inflammatory and anti-platelet effects. COX-2 is inducible, produced under inflammatory and neoplastic circumstances, and is responsible for pathological prostaglandins which produce inflammation, pain and fever. COX-2 selective drugs have become one of the most successful commercial ventures yet because of the effect on these prostaglandins but without the gastrointestinal effects of the non-selective inhibitors. Paracetamol has analgesic and antipyretic effects (and weak anti-inflammatory effects), suggesting that it acts on a different COX form, possibly COX-3. This variant has now been localised to brain and spinal cord. Specific COX-2 inhibitors have no COX-3 effects while other NSAIDS such as ibuprofen, diclofenac and indomethacin show the most powerful COX-3 inhibition (implying 'spillover' to other COXs). Read more: Lancet 2003;361:981-2, and 2002;355:646-68 Clin Infect Dis 2000;31:S202-10 |