A 48-year-old woman ventilated in the ICU receives a vecuronium infusion for 5 days. After discontinuation she has prolonged generalised weakness lasting over 24 hours. The most likely explanation is:

• A Hofmann elimination failure due to acidosis
• B Accumulation of the active metabolite 3-desacetylvecuronium ✓
• C Development of a phase II block identical to succinylcholine dual block
• D Antibodies against the nicotinic receptor induced by prolonged exposure

Explanation

Vecuronium undergoes hepatic deacetylation to 3-desacetylvecuronium, an active metabolite with about 80% of the parent compound's potency. It is renally excreted, so it accumulates with prolonged infusions and renal impairment, causing prolonged weakness. Hofmann elimination applies to atracurium and cisatracurium, which are therefore preferred for ICU infusions.

Reference: Miller's Anesthesia, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.