How Rofecoxib Targets Inflammation Without Harming the Stomach
Rofecoxib, sold as Vioxx, selectively inhibits cyclooxygenase-2 (COX-2), the enzyme that produces prostaglandins driving pain and inflammation in injured tissues.[1] Unlike traditional NSAIDs like ibuprofen, which block both COX-1 and COX-2, rofecoxib spares COX-1.[1][2]
Why COX-1 Matters for Stomach Protection
COX-1 generates prostaglandins that maintain the stomach's protective mucus lining and regulate acid secretion, preventing ulcers and bleeding.[2][3] By avoiding COX-1 inhibition, rofecoxib reduces these gastrointestinal risks—clinical trials showed ulcer rates under 1% with rofecoxib versus 5-10% with non-selective NSAIDs.[3]
What Happens with Non-Selective NSAIDs
Drugs inhibiting both enzymes cut protective prostaglandins, eroding the stomach barrier and raising ulcer risk by 2-4 times.[2] Rofecoxib's COX-2 specificity sidesteps this, offering pain relief with a safer GI profile.[1]
Limits and Real-World Evidence
Protection isn't absolute—high doses or long-term use still caused some GI issues in 0.5-2% of patients, per studies.[3] Rofecoxib was withdrawn in 2004 for heart risks, not stomach problems.[1]
[1]: FDA Label for Vioxx (rofecoxib)
[2]: NEJM: COX-2 Inhibitors and GI Safety (2000)
[3]: Lancet: VIGOR Trial on Rofecoxib GI Effects (2000)