Vecuronium (Norcuron) is a muscle relaxant in the category of non-depolarizing blocking agents. Vecuronium bromide is indicated as an adjunct to general anesthesia, to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical
ventilation. Although vecuronium bromide is often thought of as a muscle relaxant, it may be more accurate to classify it as a paralyzing agent. It is commercially available as ampoules containing 4 mg of the drug in powder form which needs to be dissolved in distilled water prior to administration to the patient. In India, vials containing 10 mg of vecuronium bromide are also commercially available, for use in patients undergoing prolonged surgical procedures.
Vecuronium's structure is derived from the same aminosteroid structure as pancuronium, but it is missing the methyl group on the piperidine nitrogen that is attached to the 'A' ring, making it monoquaternary, like D-tubocurarine. This means it is less potent than pancuronium as a neuromuscular blocking agent. It has the same configuration at all ten stereocentres as pancuronium, and is a single-isomer preparation.
Vecuronium operates by competing for the cholinoceptors at the motor end plate thereby exerting its muscle-relaxing properties which are used adjunctively to general anesthesia. Under balanced anesthesia, the time to recovery to 25% of control (clinical duration) is
approximately 25 to 40 minutes after injection and recovery is usually 95% complete
approximately 45 to 65 minutes after injection of intubating dose. The neuromuscular
blocking action of vecuronium is slightly enhanced in the presence of potent inhalation
anesthetics. If vecuronium is first administered more than 5 minutes after the start of the
inhalation of enflurane, isoflurane, or halothane, or when a steady state has been achieved, the intubating dose of vecuronium may be decreased by approximately 15%.