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Remifentanil metabolism — FRCA Primary MCQ

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ModeratePharmacologyRemifentanil metabolismFRCA Primary

During a prolonged neurosurgical case, remifentanil is used because rapid offset is desired after stopping the infusion. Which process explains this predictable recovery?

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Correct answer: B — Hydrolysis by nonspecific esterases

Remifentanil is rapidly hydrolysed by nonspecific blood and tissue esterases, so its context-sensitive half-time remains short. Renal excretion does not determine offset, although inactive metabolites are renally cleared. Hepatic glucuronidation is more relevant to morphine. Its rapid offset can lead to acute pain or sympathetic activation unless longer-acting analgesia is planned.

Reference: Peck, Hill & Williams Pharmacology for Anaesthesia and Intensive Care