NSAIDs provide analgesia by inhibiting cyclooxygenase enzymes. Which combination of enzymes is targeted?

• A. COX-3 only
• B. COX-1 and COX-2
• C. 5-LOX
• D. PLA2

Answer: (B)

NSAIDs relieve pain by blocking enzymes that convert arachidonic acid into inflammatory mediators. The key players are cyclooxygenases, with two main forms in humans: COX-1, which is normally present and helps protect the stomach lining and support platelets, and COX-2, which is produced during inflammation to drive pain and swelling. Inhibiting both COX-1 and COX-2 cuts down on prostaglandin synthesis, leading to analgesia, anti‑inflammation, and fever reduction. Some NSAIDs are more selective for COX-2 to lessen GI side effects, but the broad action targets both enzymes. Other enzymes like 5-LOX (leukotriene production) or PLA2 (releases arachidonic acid) are not the primary targets of classic NSAIDs, and COX-3 is not the main clinically relevant target. Therefore, the combination is COX-1 and COX-2.