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Renal Failure NMB Duration — FRCA Primary MCQ

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ModeratePharmacology - NeuromuscularRenal Failure NMB DurationFRCA Primary

An adult with end-stage renal failure and no known plasma cholinesterase abnormality receives a usual single intubating dose of one of the following non-depolarising neuromuscular blocking agents. Which agent is expected to produce the longest duration of neuromuscular block?

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Correct answer: C — Pancuronium

Pancuronium is a long-acting aminosteroid neuromuscular blocker whose clearance is substantially reduced in renal failure. Human studies demonstrate delayed recovery, wide variability and accumulation in anephric or end-stage renal failure, so it produces the longest block among these options. Atracurium and cisatracurium are inactivated predominantly by organ-independent Hofmann degradation; their recovery profiles are largely unaffected by renal failure. Mivacurium is hydrolysed by plasma cholinesterase. Its block is about 1.5 times longer in end-stage renal failure, but it remains relatively short acting when a plasma cholinesterase abnormality is excluded. Rocuronium is eliminated in bile and urine and may be prolonged in renal failure, but usually less markedly in absolute duration than pancuronium. Quantitative neuromuscular monitoring remains essential.

Reference: Berntman L, Rosberg B, Shweikh I, Yousef H. Atracurium and pancuronium in renal insufficiency. Acta Anaesthesiologica Scandinavica. 1989;33:48–52. https://pubmed.ncbi.nlm.nih.gov/636802/