A 40-year-old woman with rheumatoid arthritis is switched from diclofenac to celecoxib (a COX-2 selective inhibitor). Which adverse effect profile best distinguishes celecoxib from diclofenac?

• A Lower risk of both GI ulceration and cardiovascular events
• B Higher hepatotoxicity but lower nephrotoxicity
• C Greater anti-inflammatory effect with no effect on platelet function
• D Lower risk of GI ulceration but higher risk of thrombotic cardiovascular events ✓

Explanation

COX-2 selective inhibitors spare COX-1 in the gastric mucosa, preserving prostaglandin E2-mediated gastroprotection and causing fewer GI ulcers and bleeding episodes. However, COX-2 inhibition in endothelial cells reduces prostacyclin (PGI2) production while platelet thromboxane A2 synthesis via COX-1 remains intact, shifting the haemostatic balance towards thrombosis and increasing myocardial infarction and stroke risk. Both non-selective NSAIDs and COX-2 inhibitors impair renal prostaglandin synthesis similarly, so nephrotoxicity risk is comparable.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.