Selective COX-2 inhibitors and gastrointestinal mucosal injury: pharmacological and therapeutic considerations

It is well recognized that nonsteroidal antiinflammatory drugs (NSAIDs) induce gastrointestinal (GI) ulcerations, perforation and bleeding, which clearly limit their therapeutic value. The recent introduction of NSAIDs with selective cyclooxygenase-2 (COX-2) inhibitory effect is a major pharmacologic milestone in therapeutics. Selective COX-2 inhibitors exhibit considerable dissociation between their antiinflammatory/analgesic action and their GI toxicity. However, from a therapeutic consideration, there are still several unresolved and confusing issues with these drugs such as: the pharmacologic classification of the COX-2 selectivity; therapeutic value as antirheumatic/analgesic drugs; potential toxicity in patients at risk for the development of ulcer-related complications or patients with inflammatory bowel disease and potential renal toxicity. Although existing clinical efficacy studies with celecoxib and rofecoxib, two selective COX-2 inhibitors, were associated with considerably lower ulcerogenic rates when compared with nonselective NSAIDs, there are no long term outcome studies with these drugs similar to the MUCOSA trial performed with misoprostol. Furthermore, the selectivity of COX-2 inhibitors appears to be specific to the stomach and duodenum but not the kidney. While awaiting additional long term studies with selective COX-2 inhibitors, we recommend instituting prophylactic therapy with misoprostol in patients at risk for the development of ulcer related complications. In conclusion, we believe that the introduction of selective COX-2 inhibitors will revolutionize the treatment of pain and inflammation. However, additional basic and clinical studies are required to address the pharmacologic and therapeutic uncertainties for this class of drugs.