|Other names||Pancuronium bromide|
|Drug class||Neuromuscular blocking agent|
|Main uses||Relax muscles during general anesthesia or during intubation and ventilation|
|Side effects||Muscle weakness, anaphylaxis, increased heart rate|
|Onset of action||2 to 3 min|
|Duration of action||Up to 100 min|
|Typical dose||0.04 to 0.1 mg/kg|
|Protein binding||77 to 91%|
|Elimination half-life||1.5 to 2.7 hours|
|Excretion||Kidney and biliary|
|Chemical and physical data|
|Molar mass||572.875 g·mol−1|
Pancuronium, sold under the brand name Pavulon, is a medication used to relax muscles during general anesthesia, when a person is being ventilated, and to help with endotracheal intubation. It is given by injection into a vein. Onset is relatively slow at 2 to 3 minutes while effects can last for up to 100 minutes.
Common side effects include muscle weakness. Other side effects may include anaphylaxis and increased heart rate. Use in pregnancy appears to be safe, but is not well studied. Neostigmine or pyridostigmine may be used to reverse its affects. It is a neuromuscular blocking agent.
Pancuronium was first made in 1964 and approved for medical use in the United States in 1972. It is available as a generic medication. In the United Kingdom it costs the NHS about £5 per 4 mg as of 2021. This amount is about 3 USD in the United States. It has been used in euthanasia and during lethal injection.
In Belgium and the Netherlands, pancuronium is recommended in the protocol for euthanasia. After administering sodium thiopental to induce coma, pancuronium is delivered in order to stop breathing.
The typical initial dose is 0.04 to 0.1 mg/kg with further doses of 0.01 mg/kg as needed. May also be given as an infusion at 0.7 to 2 mcg/kg/min. The dose is based on a persons ideal body weight.
Sideeffects include moderately raised heart rate and thereby arterial pressure and cardiac output, excessive salivation, apnea and respiratory depression, rashes, flushing, and sweating.[medical citation needed] The muscular relaxation can be dangerous in the seriously ill and it can accumulate leading to extended weakness. Pancuronium is not preferable in long-term use in ICU-ventilated patients.
Mechanism of action
Pancuronium is a typical non-depolarizing curare-mimetic muscle relaxant. It competitively inhibits the nicotinic acetylcholine receptor at the neuromuscular junction by blocking the binding of acetylcholine. It has slight vagolytic activity, causing an increase in heart rate, but no ganglioplegic (i.e., blocking ganglions) activity. It is a very potent muscle relaxant drug, with an ED95 (i.e., the dose that causes 95% depression of muscle twitch response) of only 60 µg/kg body weight. Onset of action is relatively slow compared to other similar drugs, in part due to its low dose: an intubating dose takes 3–6 minutes for full effect. Clinical effects (muscle activity lower than 25% of physiological) last for about 100 minutes. The time needed for full (over 90% muscle activity) recovery after single administration is about 120–180 minutes in healthy adults.
Pancuronium is designed to mimic the action of two molecules of acetylcholine with the quaternary nitrogen atoms spaced rigidly apart by the steroid rings at a distance of ten atoms (interonium distance). Decamethonium and suxamethonium also have this same interonium distance.
Society and culture
Like all non-depolarising muscle relaxants, pancuronium has no effect on level of consciousness. Therefore, if the anaesthetic used is insufficient, the individual may be awake but unable to cry out or move due to the effect of the pancuronium. There have been several civil lawsuits alleging similar failures of adequate anaesthesia during general surgical procedures. These have been largely due to improper or insufficient dosages of anaesthetic in concert with normal dosages of muscle relaxants such as pancuronium.
In 2007, Michael Munro, a Scottish neonatologist at Aberdeen Maternity Hospital, was cleared of malpractice by the GMC Fitness to Practice panel after giving 23 times the standard dose of pancuronium to two dying neonates. Terminally ill, both dying babies were suffering from agonal gasping and violent body spasms, which was highly distressing for the parents to witness. Munro then administered pancuronium to the babies after advising the parents that this would ease their suffering and could also hasten death. It is on record that neither of the children's parents were unhappy with Dr Munro's treatment of their babies.
Amnesty International has objected to its use in lethal injections on the grounds that it "may mask the condemned prisoner's suffering during the execution," thereby leading observers to conclude that lethal injection is painless, or less cruel than other forms of execution.
The United Kingdom bans the export of pancuronium bromide to the United States due to its use in lethal injections, but not to Netherlands or Belgium.
Uses in crime
Pancuronium was used in Efren Saldivar's killing spree. It was also used by the Skin Hunters to kill patients in the Polish city of Łódź. Pavulon was also used by Richard Angelo in 1987 to kill at least 10 patients under his care at the Good Samaritan Hospital in New York.
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