About Nimesulide COX-2 selective NSAID, Analgesic,antipyretic. Mechanism of Action of Nimesulide This Non Steroidal Anti Inflammatory Drug reduces prostaglandin synthesis by the inhibition of cyclo oxygenase enzyme2 selectively. This is a weaker inhibition .So it produces weaker analgesic property. Its potent anti-inflammatory activity is due to its action on various stages of inflammation. This leads to the inhibition of super oxide anion formation invitro by activated neutrophil, inhibition of histamine release from tissue mast cells and basophiles. Additionally it also prevents platelet activating factor synthesis and metalloproteinase synthesis thus prevents the breakdown of osteoarthritic human cartilage. It also prevent tumor necrosis factor alpha and thus reduce the formation of cytokines. This drug can activate glucocorticoid receptors in the body.