NSAID Mechanism — MFDS Part 1 MCQ

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EasyPharmacologyNSAID MechanismMFDS Part 1

Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, exert their analgesic and anti-inflammatory effects primarily by inhibiting which enzyme?

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Correct answer: E — Cyclo-oxygenase

The correct answer is E, cyclo-oxygenase (COX). NSAIDs primarily inhibit COX-1 and/or COX-2, reducing the conversion of arachidonic acid into prostaglandin precursors. Reduced prostaglandin production limits inflammatory signalling and peripheral sensitisation of nociceptors, producing anti-inflammatory and analgesic effects. Lipoxygenase instead generates leukotrienes and is not the principal target of conventional NSAIDs. Phospholipase A2 releases arachidonic acid from membrane phospholipids and is suppressed indirectly by glucocorticoids rather than NSAIDs. Acetylcholinesterase terminates acetylcholine signalling, while monoamine oxidase metabolises monoamine neurotransmitters; neither explains the characteristic effects of NSAIDs.

Reference: Electronic Medicines Compendium, Ibuprofen 600 mg film-coated tablets, Summary of Product Characteristics, section 5.1 Pharmacodynamic properties, revised 2026. https://www.medicines.org.uk/emc/product/7021/smpc