Vecuronium

BRAND NAMES: Norcuron, vecuronium.

INDICATIONS:

	Adjunct to general anesthesia to facilitate endotracheal intubation.
	Skeletal muscle relaxation during surgery or mechanical ventilation.
	Short ambulatory surgery requiring muscle relaxation.
	Intubation for patients with ischemic heart disease.

CLASS: Synthetic monoquaternary aminosteroid non-depolarizing neuromuscular blocker. Intermediate-acting, non-depolarizing muscle relaxant.

MODE OF ACTION:

	Competitive antagonist of acetylcholine on the alpha subunit of the nicotinic post-junctional receptor. Prevents opening of the ion channel of the receptor.
	Interferes with the mobilization of acetylcholine presynaptically.
	May block the open receptor and interferes with the passage of ions.
	Vecuronium is produced by demethylation of the pancuronium molecule, significantly reducing its vagolytic property and increasing lipid solubility. More potent than pancuronium, with a shorter duration of action. No sympathomimetic or vagolytic effects, does not release histamine. Incompatible with alkaline solutions, pH > 8.5. Vecuronium inhibits histamine metabolism at doses > 0.1 mg/kg.

ONSET:

	ED95 (dose producing 95% of maximum neuromuscular block at the adductor pollicis): 0.04 mg/kg.
	Onset time (to maximum effect): 3 min at 2 × ED95.
	Intubation: 2-3 min, more rapid in infants (1.5 min) than in adults.

DURATION:

	Clinical duration of action (to 25% recovery): 30-40 min at 2 × ED95.
	Total duration of action (to 90% recovery): 50-60 min at 2 × ED95.
	20-40 min effective block, 95% recovery 45-65 min. Duration of action is longest in infants (70 min), shortest in children (35 min). Duration of action prolonged in obesity (> 130% ideal body weight). Reduced potency and duration in men. Large volume of distribution.
	Recovery index (time from 25 to 75% recovery): 12 min.

CLEARANCE:

	Undergoes spontaneous desacetylation to 3-OH, 17-OH and 3-17 di-OH metabolites although some of these metabolites are also formed in the liver.
	Most potent metabolite is the 3-OH derivative, which is as potent as vecuronium.
	Vecuronium and the 3-OH derivative are eliminated by the kidney.
	Biliary excretion (unchanged) 40-60%, hepatic 20%, renal elimination 10-20%. The 3-desacetyl vecuronium is responsible for prolonged paralysis in ICU patients. Clearance may be accelerated during late pregnancy, prolonged in post-partum. Protein binding 60-80%; clearance, adults 3 mL/kg/min, neonates 5.6 mL/kg/min.

ADULT DOSE:

	Intubation: 0.08-0.1 mg/kg IV.
	Priming: 0.01 mg/kg IV followed 3-4 min later by 0.1 mg/kg IV (onset 1.5 min).
	Following initial dose of succinylcholine: 0.07 mg/kg IV.
	Maintenance doses should be given carefully using a nerve stimulator: 0.025 mg/kg IV or continuous infusion 1-2 µg/kg/min. Interval between doses should be lengthened in cases of severe renal or hepatic failure.
	Large doses (0.2-0.4 mg/kg IV) have been used to provide rapid intubating conditions with an onset of 1.5–2 min. Duration of action will then be prolonged to 90-120 min.
	Dosage should be based on ideal body weight in obese patients.
	Reduce dosage in elderly patients (decreased hepatic/renal clearance).

PEDIATRIC DOSE:

	> 7 weeks-1 yr 0.08-0.1 mg/kg IV, maintenance 0.01-0.015 mg/kg every 40-60 min.
	> 1 yr 0.08-0.1 mg/kg IV, maintenance 0.01-0.015 every 25-40 min.
	1-10 yr may require a slightly higher dose and more frequently.
	Infants (> 7 weeks-1 yr) more sensitive to vecuronium, recovery time prolonged, due to immature liver enzymes and an increased volume of distribution.

NEONATAL DOSE:

	0.1 mg/kg IV, maintenance 0.03-0.15 mg every 1-2 h.
	Duration increased in newborns with hepatic or renal impairment.
	Bradycardia and hypotension may occur with concurrent opioid administration.
	Use with caution in neonates with neuromuscular disease.
	Do not reconstitute with diluents containing benzyl alcohol.

CAUTION:

	Hepatic impairment (reduce dose in cirrhosis or cholestasis).
	Renal impairment (prolongs neuromuscular blockade).
	Dosage should be based on ideal body weight in obese patients.
	No counteraction of bradycardia produced by anesthetics or vagal stimulation.
	Increased incidence of bradycardia with potent opioids.
	Neuromuscular disorders, refer to pancuronium for detailed listing.
	Incompatible with alkaline solutions, pH > 8.5.
	Precipitates with barbiturates (thiopental); may occlude IV line.

CONTRAINDICATIONS: Hypersensitivity to vecuronium. Not for IM injection.

INTERACTIONS: Inhalational agents prolong neuromuscular blockade. Hypercarbia significantly enhances vecuronium. See pancuronium for detailed listing.

ADVERSE REACTIONS:

	CVS: bradycardia, hypotension, tachycardia, flushing, arrhythmias.
	Pulmonary: prolonged paralysis and generalized myopathy in ICU patients.
	Other: anaphylaxis, itching, rash.

PREGNANCY: Category C.

OBSTETRICS: Caution: 0.2 mg/kg for rapid sequence induction may cause paralysis for almost 2 h!

COMMENTS: After reconstitution of the lyophilized powder solution remains stable for 24 h.