A 7-year-old child presents with fever and joint pain following a viral illness. The physician avoids prescribing aspirin and instead uses acetaminophen (paracetamol). What is the primary mechanism by which acetaminophen produces its antipyretic and analgesic effects?

• A Reversible inhibition of central COX isoforms with minimal peripheral anti-inflammatory activity ✓
• B Reversible inhibition of peripheral COX-1 and COX-2 with anti-inflammatory action
• C Irreversible acetylation of the COX active site in both platelets and endothelial cells
• D Selective inhibition of the lipoxygenase pathway of arachidonic acid metabolism

Explanation

Acetaminophen inhibits central COX isoforms, giving antipyretic and analgesic effects, but has minimal peripheral anti-inflammatory action because it is inactivated in inflamed tissues by high peroxide concentrations. This is the reason it is not classified as a traditional NSAID and does not cause significant GI toxicity or antiplatelet effects at therapeutic doses.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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