VECURONIUM BROMIDE
Chemistry - Structurally similar to pancuronium, vecuronium bromide is a synthetic, nondepolarizing neuromuscular blocking agent. It contains the steroid (androstane) nucleus, but is devoid ofsteroid activity. It occurs as white to off-white, or slightly pink crystals or crystalline powder. Inaqueous solution it has a pKa of 8.97, and the commercial injection has a pH of 4 after reconstitution. 9 mg are soluble in 1 ml of water; 23 mg are soluble in 1 ml of alcohol. Vecuronium mayalso be called:Org NC 45.
Vecuronium bromide has been shown to be physically compatible with D5W, normal saline, D5 innormal saline, and lactated Ringer's. It should not be mixed with alkaline solutions (e.g., thiobarbiturates).
Uses, Indications - Vecuronium is indicated as an adjunct to general anesthesia to produce musclerelaxation during surgical procedures or mechanical ventilation and also to facilitate endotrachealintubation. It has very minimal cardiac effects and generally does not cause the release of histamine.
Vecuronium is partially metabolized; it and its metabolites are excreted into the bile and urine.
Prolonged recovery times may result in patients with significant renal or hepatic disease.
Contraindications/Precautions - Vecuronium is contraindicated in patients hypersensitive to it. Itshould be used with caution in patients with severe renal dysfunction. Lower doses may benecessary in patients with hepatic or biliary disease. Vecuronium has no analgesic or sedative/anesthetic actions. In patients with myasthenia gravis, neuromuscular blocking agents should beused with extreme caution, if at all. One case of successful use in a dog with myasthenia gravis hasbeen reported.
Overdosage - No cases of vecuronium overdosage have yet been reported (human or veterinary).
Should an inadvertent overdose occur, treat conservatively (mechanical ventilation, O2, fluids, etc.).
Reversal of blockade might be accomplished by administering an anticholinesterase agent(edrophomium, physostigmine, or neostigmine) with an anticholinergic (atropine or glycopyrrolate).
A suggested dose for neostigmine is 0.06 mg/kg IV after atropine 0.02 mg/kg IV.
Storage, Stability, Compatibility
The commercially available powder for injection should bestored at room temperature and protected from light. After reconstitution with sterile water for injection, vecuronium bromide is stable for 24 hours at either 2-8°C or at room temperature (less than30°C) if stored in the original container. As it contains no preservative, unused portions should bediscarded after reconstitution. It has been demonstrated that the drug is stable for 48 hours whenrefrigerated or kept at room temperature when stored in plastic or glass syringes, but themanufacturer recommends that it be used within 24 hours.Vecuronium bromide has been shown to be physically compatible with D5W, normal saline, D5 innormal saline, and lactated Ringer's. It should not be mixed with alkaline solutions (e.g., thiobarbiturates).
Pharmacology - VECURONIUM BROMIDE
Vecuronium is a nondepolarizing neuromuscular blocking agent and acts bycompetitively binding at cholinergic receptor sites at the motor end-plate, thereby inhibiting theeffects of acetylcholine. The potency of vecuronium when compared to pancuronium has beendescribed as being from 3 times as potent to equipotent on a weight basis.Uses, Indications - Vecuronium is indicated as an adjunct to general anesthesia to produce musclerelaxation during surgical procedures or mechanical ventilation and also to facilitate endotrachealintubation. It has very minimal cardiac effects and generally does not cause the release of histamine.
Pharmacokinetics - VECURONIUM BROMIDE
The onset of neuromuscular blockade after IV injection is dependent upon thedose administered. In dogs administered 0.1 mg/kg IV, full neuromuscular block occurs within 2minutes and the duration of action at this dose is approximately 25 minutes (also receivinghalothane anesthesia). Vecuronium has a shorter duration of action than pancuronium (approx. 1/3- 1/2 as long), but is very similar to that of atracurium.Vecuronium is partially metabolized; it and its metabolites are excreted into the bile and urine.
Prolonged recovery times may result in patients with significant renal or hepatic disease.
Contraindications/Precautions - Vecuronium is contraindicated in patients hypersensitive to it. Itshould be used with caution in patients with severe renal dysfunction. Lower doses may benecessary in patients with hepatic or biliary disease. Vecuronium has no analgesic or sedative/anesthetic actions. In patients with myasthenia gravis, neuromuscular blocking agents should beused with extreme caution, if at all. One case of successful use in a dog with myasthenia gravis hasbeen reported.
Adverse Effects, Warnings
In human studies and in one limited dog study, adverse effects otherthan what would be seen pharmacologically (skeletal muscle weakness to profound, prolongedmusculoskeletal paralysis) have not been reported.Overdosage - No cases of vecuronium overdosage have yet been reported (human or veterinary).
Should an inadvertent overdose occur, treat conservatively (mechanical ventilation, O2, fluids, etc.).
Reversal of blockade might be accomplished by administering an anticholinesterase agent(edrophomium, physostigmine, or neostigmine) with an anticholinergic (atropine or glycopyrrolate).
A suggested dose for neostigmine is 0.06 mg/kg IV after atropine 0.02 mg/kg IV.