Abstract

Inhibition of cyclooxygenase(COX), and thus prevention of the formation of prostaglandins, provided a unifying explanation of the therapeutic and toxic actions of nonsteroidal anti-inflammatory drugs(NSAIDs). Recently, the discovery of the two isoforms of COX was made by molecular biologists studying neoplastic transformation in chick embryo cells. The constitutive enzyme, COX-1, is obviously responsible for the production of prostaglandins involved in housekeeping functions such as maintenance of integrity of the gastric mucosa, renal blood flow and platelet aggregation. The inducible form of COX(COX-2) is responsible for the formation of prostaglandins that pathologic effects of inflammation, pain and fever. Clearly, all the experimental and clinical data support the hypothesis that the beneficial effects of NSAIDs are due to inhibition of the COX-2 enzyme, whereas the gastrotoxicity is due to inhibition of COX-1. The COX-2/COX-1 ratios of the NSAIDs in common use have been measured and compared with epidemiological data on their side effects. there is little evidence to suggest that one NSAID is clearly more efficacious than another and substantial individual variability is present with respect to the pharmacology and pharmacokinetics of these drugs, it is essential to adjust the dosage and choose specific drug to the patient`s response.

• Keywords: Nonsteroidal anti-inflammatory drugs;Prostaglandin;COX-1;COX-2;