Review Question - QID 107009

This gentleman most likely has a gastric ulcer caused by the daily use of aspirin, an irreversible, non-selective cyclooxygenase (COX) 1 and 2 inhibitor. This gastric ulcer could have been prevented by the use of a selective COX-2 inhibitor, such as celecoxib, instead of aspirin.

Aspirin is a NSAID that irreversibly inhibits both COX-1 and -2 by forming a covalent bond with the enzymes. As a result, it causes a decrease in the production of prostaglandins and thromboxanes. COX-1 is found in many tissues and is responsible for the maintaining mucosal integrity. If COX-1 is inhibited, the mucus lining is no longer being produced and the gastric lining is now vulnerable to gastric acid; this can result in gastric ulcers. COX-2 is found primarily in inflammatory cells, and inhibition of COX-2 prevents the inflammatory response. Therefore, non-selective inhibition of COX-1 and -2 results in anti-inflammatory effects as well as a decrease in gastric mucus secretion. Therefore, it is advantageous to selectively block COX-2 by the use of selective COX-2 inhibitors such as celecoxib.

Incorrect Answers:
Answer 1-4: These are non-selective COX inhibitors and would still increase the risk of developing gastric ulcers.