Vecuronium Metabolite — FRCA Primary MCQ

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HardPharmacology - NeuromuscularVecuronium MetaboliteFRCA Primary

A patient with acute kidney injury has persistent train-of-four suppression after a prolonged vecuronium infusion has been stopped. Accumulation of which pharmacologically active metabolite may contribute to the prolonged neuromuscular block?

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Correct answer: C — 3-desacetylvecuronium

The correct answer is C, 3-desacetylvecuronium, also described as 3-hydroxyvecuronium. It is the principal pharmacologically active metabolite of vecuronium and retains substantial competitive neuromuscular-blocking activity. Its clearance is lower and terminal elimination half-life longer than those of the parent drug, so accumulation may contribute to persistent paralysis after prolonged administration, particularly with renal dysfunction. Laudanosine is produced during atracurium and cisatracurium degradation and is associated mainly with central nervous system excitation rather than neuromuscular block. Norketamine is an active ketamine metabolite; norfentanyl is a largely inactive fentanyl metabolite; and O-desmethyltramadol is an active opioid metabolite of tramadol.

Reference: Caldwell JE et al. The pharmacodynamics and pharmacokinetics of the metabolite 3-desacetylvecuronium (ORG 7268) and its parent compound, vecuronium, in human volunteers. Journal of Pharmacology and Experimental Therapeutics. 1994;270:1216–1222. https://pubmed.ncbi.nlm.nih.gov/7932174/