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 is approximately 25 to 40 minutes after injection and recovery is usually 95% complete approximately 45 to 65 minutes after injection of an 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%. Vecuronium has an active metabolite, 3-desacetyl-vecuronium, that has 80% of the effect of vecuronium. Accumulation of this metabolite, which is cleared by the kidneys, can prolong the duration of action of the drug, particularly when an infusion is used in a person with kidney failure. Reversal of vecuronium can be accomplished by administration of sugammadex which is a γ-cyclodextrin which encapsulates vecuronium preventing it from binding to receptors. Reversal can also be accomplished with neostigmine or other cholinesterase inhibitors, but their efficacy is lower than that of sugammadex.
History
As long ago as 1862, adventurer Don Ramon Paez described a Venezuelan poison, guachamaca, which the indigenous peoples used to lace sardines as bait for herons and cranes. If the head and neck of a bird so killed was cut off, the remainder of the flesh could be eaten safely. Paez also described the attempt of a Llanero woman to murder a rival to her lover's affections with guachamaca and unintentionally killed 10 other people when her husband shared his food with their guests. It is probable that the plant was Malouetia nitida or Malouetia schomburgki. The genus Malouetia is found in both South America and Africa. The botanist Robert E. Woodson Jr comprehensively classified the American species of Malouetia in 1935. At that time, only one African species of Malouetia was recognised, but the following year Woodson described a second: Malouetia bequaertiana, from the Belgian Congo. It was in 1960 that scientists reported the isolation of malouetine from the roots and bark of Malouetia bequaertiana Woodson by means of an ion exchange technique. A pure form of the substance was first synthesised in 1964, and was named pancuronium bromide. The name was derived from pancur-onium. A paper published in 1973 discussed the structure-activity relationships of a series of aminosteroid muscle relaxants, including the mono-quaternary analogue of pancuronium, later called vecuronium.
Society and culture
It is commercially available as ampoules containing 4 or 10 mg of the drug in powder form which needs to be dissolved in distilled water prior to being given.
Non-medical use
Vecuronium bromide has been used as part of a drug cocktail that prisons in the United States use as a means to put a condemned prisoner to death. Vecuronium is used to paralyze the prisoner and stop his or her breathing, in conjunction with a sedative and potassium chloride to stop the prisoner's heart. Injections of vecuronium bromide without proper sedation allow the person to be fully awake but unable to move in response to pain. In 2001, Japanese nurse Daisuke Mori was reported to have murdered 10 patients using vecuronium bromide. He was convicted of murder and was sentenced to life imprisonment.
