Acetaminophen inhibition is thought to involve which COX enzyme?

Acetaminophen inhibition is thought to involve which COX enzyme?

• A. COX-2
• B. 5-LOX
• C. COX-1
• D. Phospholipase A2

Answer: (A)

Acetaminophen works mainly by inhibiting prostaglandin synthesis in the brain, targeting a brain COX form that functions like COX-2 in the CNS. This central COX-2–type enzyme reduction lowers hypothalamic prostaglandin E2, which resets the body's temperature set point (antipyretic effect) and dampens pain signals. Peripheral COX-1/COX-2 in inflamed tissues aren’t effectively blocked by acetaminophen, which explains its weak anti-inflammatory action. The drug’s action is less about the enzymes in the leukotriene pathway (5-LOX) or upstream phospholipase A2, and more about this CNS COX-2–like target.

Acetaminophen works mainly by inhibiting prostaglandin synthesis in the brain, targeting a brain COX form that functions like COX-2 in the CNS. This central COX-2–type enzyme reduction lowers hypothalamic prostaglandin E2, which resets the body's temperature set point (antipyretic effect) and dampens pain signals. Peripheral COX-1/COX-2 in inflamed tissues aren’t effectively blocked by acetaminophen, which explains its weak anti-inflammatory action. The drug’s action is less about the enzymes in the leukotriene pathway (5-LOX) or upstream phospholipase A2, and more about this CNS COX-2–like target.