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Sugammadex mechanism of action — FRCA Primary MCQ

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ModeratePharmacologySugammadex mechanism of actionFRCA Primary

A patient receives sugammadex after rocuronium. Within three minutes the train-of-four ratio improves from 0.28 to 0.94. Which mechanism best explains this reversal?

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Reveal the answer and explanation

Correct answer: C — Inhibition of acetylcholinesterase at the neuromuscular junction

Sugammadex is a modified cyclodextrin that encapsulates aminosteroid neuromuscular blockers such as rocuronium in plasma, reducing free drug concentration. Neostigmine reverses block by acetylcholinesterase inhibition, which is a different mechanism and less effective for deep block. Sugammadex does not enhance hepatic metabolism. The pearl is that sugammadex reversal depends on the specific neuromuscular blocker used.

Reference: RCoA Primary FRCA Syllabus 2026; Peck, Hill & Williams Pharmacology for Anaesthesia