New NSAIDs and gastroduodenal damage.

Two isoforms of cyclooxygenase (COX) are described: COX-1 is a constitutive enzyme and is widely expressed in most tissues, COX-2 is an inducible enzyme and is abundant throughout the gastrointestinal tract. Expression of COX-2 can be induced locally by inflammatory stimuli and appears coincident with local prostaglandin (PG) production. Currently available non-steroidal antiinflammatory drugs (NSAIDs) are widely used for the treatment of inflammatory diseases; however, significant side-effects due to inhibition of COX-1 limit their use. Inhibitors of COX-2 are as active as non-selective NSAIDs and inhibit PG synthesis in inflammatory cells. In contrast to other NSAIDs, selective COX-2 inhibitors do not cause ulcers in the stomach or intestine.