Cyclooxygenase -1/2 inhibition

NSAIDs are classified as non-selective (they inhibit COX-1 and COX-2) or selective (they inhibit only COX-2) based on degree of cyclooxygenase inhibition. COX-2 inhibition is responsible for anti-inflammatory effects, while COX-1 inhibition contributes to increased GI and renal toxicity associated with non-selective agents. Since the antiplatelet effect of non-selective NSAIDs is reversible, concurrent use may reduce the... 

D19. Dinarello, C. A., Okusawa, S., and Gelfland, J. A., Interleukin-1 induces a shock-like state in rabbits Synergism with tumor necrosis factor and the effect of cyclooxygenase inhibition. In Molecular and Cellular Mechanisms of Septic Shock. Alan R. Liss, New York, 243-263... 

The widely used platelet inhibitor aspirin or acetylsalicylic acid, by acetylating the enzyme cyclooxygenase, inhibits platelet function by preventing the formation of thromboxane A2 and the synthesis of prostaglandin I2 (PGI2) (68). Aspirin has been used in combination with other antiplatelet agents such as ticlopidine, which inhibits ADP-induced platelet aggregation (69). 

Binds to DNA and prevents separation of the helical strands Affects neuronal transmissions Binds to opiate receptors and blocks pain pathway Acts as central nervous system depressant Inhibits Na/K/ATPase, increases intracellular calcium, and increases ventricular contractibility Blocks the actions of histamine on Hi receptor Blocks ai-adrenergic receptor, resulting in decreased blood pressure Inhibits reuptake of 5-hydroxytryptamine (serotonin) into central nervous system neurons Inhibits cyclooxygenase, inhibition of inflammatory mediators Inhibits replication of viruses or tumor cells Inhibits HIV reverse transcriptase and DNA polymerase Antagonizes histamine effects... 

Piazza GA, Rahm AK, Finn T, et al. Apoptosis fully accounts for the growth inhibitory properties of sulindac metabolites by a mechanism independent of cyclooxygenase inhibition, cell cycle arrest or p53 mediation. Cancer Res 1997 57 2452-2459. 

It acts peripherally by inhibiting the synthesis of prostaglandins by reversible inhibition of cyclooxygenase. Inhibition of the migration of leukocytes to an inflammatory site and inhibition of the release of lysosomal enzymes may also be involved in the antiinflammatory action. 

In susceptibie individuais, NSAIDs may precipitate acute bronchospasm. It affects 10-20% of adults with asthma but is rare in asthmatic children. The mechanism is related to cyclooxygenase inhibition, with shunting of arachidonic acid metabolism from the prostaglandin pathway to the biosynthesis of ieukotrienes with increased mucosal permeability and bronchospasm. Susceptible patients should avoid NSAIDs since the bronchospasm may be severe and has been fatal. Paracetamol in doses up to 1000 mg daiiy wiii be toierated by most patients. True type I allergic reactions to NSAIDs, with specific IgE, are rare but anaphyloactoid reactions have occasionally been described in patients with a history of aiiergy or bronchiai asthma. 

Broussochalcone A (32) Antioxidant activity (inhibition of lipid peroxidation) Inhibition of cyclooxygenase Inhibition of nitric oxide production Inhibition of respiratory burst in neutrophils Platelet aggregation inhibitory activity1 [42] [431 [42] [44] [431... 

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