Neuromuscular blocker
Vecuronium
Indications
- Tracheal intubation and surgical relaxation when a rapid sequence is not required
- Intermittent boluses or an infusion for paralysis during mechanical ventilation in the ICU and in critical care transport
- Intubation when succinylcholine is contraindicated and rocuronium is unavailable; larger doses shorten onset but greatly lengthen the block
Dosing
Vecuronium drip card and mL/h converterStart: 0.8–1.2 mcg/kg/min after a 0.1 mg/kg bolus
| Where | Dose |
|---|---|
| Airway and RSI | Vecuronium: 0.1 mg/kg (slower onset than rocuronium; lasts 25–40 min) |
Mechanism of action
Vecuronium competes with acetylcholine for the binding sites on the α subunits of the postjunctional nicotinic receptor. A blocked site keeps the channel closed, so the end-plate potential never reaches the threshold of the surrounding sodium channels and the fiber stays relaxed, without depolarization or fasciculation. Block of prejunctional receptors limits acetylcholine mobilization and causes fade. Neostigmine overcomes the block by raising acetylcholine, and sugammadex removes the drug by encapsulation.
Pharmacology
- Neuromuscular: intermediate-acting; about six times as potent as rocuronium (ED90 about 0.057 mg/kg), so fewer molecules reach the junction and onset is slower
- Cardiovascular: no clinically significant hemodynamic effect, no vagolytic action and no histamine release; bradycardia from opioids or vagal stimuli is left unopposed
- Respiratory: apnea; no bronchospasm
- CNS: none; no sedation, amnesia or analgesia
- Other: cumulative with long infusions as the active metabolite builds up, worst in kidney failure; potentiated by volatile agents, aminoglycosides, magnesium, acidosis and hypothermia
Pharmacokinetics
| Onset | First twitch depression in about 1 min; good intubating conditions in 2.5–3 min and maximal block in 3–5 min after 0.08–0.1 mg/kg |
|---|---|
| Duration | Clinical duration 25–40 min and 95% recovery in 45–65 min after 0.08–0.1 mg/kg; much longer after large doses or infusions |
| Half-life | 65–75 min (distribution about 4 min); 35–40 min in late pregnancy |
| Distribution | Vd 0.3–0.4 L/kg; umbilical levels 11% of maternal at cesarean |
| Protein binding | 60–80% |
| Metabolism | Hepatic deacetylation to 3-desacetylvecuronium, which has at least half the parent's potency; it is excreted in urine and bile and builds up in kidney failure |
| Clearance | 3–4.5 mL/kg/min |
| Elimination | Bile 25–50% within 42 h, mostly unchanged; urine 3–35% within 24 h |
| Organ failure | Recovery can take twice as long in cirrhosis or cholestasis. After long ICU infusions in kidney failure, paralysis has lasted from 6 h to over 7 days (Segredo 1992) |
Chemistry
- Monoquaternary aminosteroid: pancuronium without the methyl on the 2-piperidine nitrogen, leaving a tertiary amine at C2, a charged N-methylpiperidinium at C16 and acetate esters at C3 and C17
- With one quaternary group instead of two it is less vagolytic and more lipid soluble than pancuronium, which favors hepatic uptake and biliary excretion
- The 3-acetate hydrolyzes in solution, aided by the neighboring 2-amine, so it comes as a lyophilized powder (10 or 20 mg) with citrate, phosphate and mannitol; pH 3.5–4.5 once reconstituted
- Single isomer. Store the powder at room temperature away from light; reconstituted drug keeps 24 h, or 5 days in bacteriostatic water, whose benzyl alcohol rules it out for newborns
Adverse effects and cautions
In the one-pagers
- Airway and RSIRSI drugs: Sugammadex reverses rocuronium or vecuronium; 16 mg/kg reverses rocuronium immediately. Watch for anaphylaxis, bradycardia; backup contraception for 7 days.
- Myasthenic Crisis and Guillain-Barré SyndromeNIV, intubation, the ventilator and liberation: Rocuronium, vecuronium: Usable; train-of-four: Very sensitive: 50–90% lower doses may suffice
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Other neuromuscular blocker drugs
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Sources
- FDA label: vecuronium bromide, Hikma (2022)
- Segredo 1992 (persistent paralysis)
- Nag 2013 (sugammadex binding)
For education and exam preparation only. Follow your institution’s protocols. Typical adult values for study. Follow the order, the label and your institution's protocols.