What Is Pancuronium Bromide?
Pancuronium bromide is a medication belonging to the class of non-depolarizing neuromuscular blocking agents. Like other drugs in this class, pancuronium is used during surgery to induce muscle relaxation and temporary paralysis. It is commonly employed in combination with general anesthesia to facilitate endotracheal intubation, mechanical ventilation, and surgical procedures.
Pancuronium works by blocking the action of acetylcholine at the neuromuscular junction, which prevents the transmission of nerve impulses to the muscles. This results in muscle relaxation and temporary paralysis. Pancuronium has an intermediate to long duration of action, making it suitable for procedures requiring prolonged muscle relaxation. The effects are reversible with the administration of drugs such as neostigmine.
Pancuronium is primarily eliminated by the kidneys, and its effects can be prolonged in individuals with impaired renal function.
It is commonly used in surgical and critical care settings where controlled muscle paralysis is required. It is especially useful in procedures where a longer duration of muscle relaxation is needed.
Pancuronium generally has a relatively rapid onset of action.
It’s important to note that the use of pancuronium bromide, like other neuromuscular blocking agents, requires careful monitoring by trained healthcare professionals. These medications are administered under the supervision of anesthesiologists or other healthcare providers with expertise in anesthesia and critical care.
On intravenous injection, pancuronium bromide is rapidly distributed into body tissues; about 80% may be bound to plasma proteins. A small proportion is metabolized in the liver to metabolites with weak neuromuscular blocking activity. It is excreted mainly in urine as unchanged drugs and metabolites; a small amount is excreted in bile. The plasma elimination half-life is about 2 hours. It crosses the placenta in small amounts.
Uses and Administration
Pancuronium bromide is an aminosteroidal competitive neuromuscular blocker (see Atracurium). Muscle relaxation occurs within about 1.5 to 2 minutes of intravenous injection and lasts 45 to 60 minutes.
Pancuronium bromide is used for endotracheal intubation to provide muscle relaxation in general anesthesia for surgical procedures (see Anaesthesia) and to aid controlled ventilation (see Intensive Care).
Doses of neuromuscular blockers need to be carefully titrated for individual patients according to response and may vary with the procedure, the other drugs given, and the state of the patient; monitoring of the degree of the block is recommended to reduce the risk of overdosage. The initial dose for intubation is usually 50 to 100 micrograms/kg by intravenous injection, with maintenance doses of 10 to 20 micrograms/kg.
Children may be given similar doses. Some manufacturers recommend reducing the initial dose to 20 to 60 micrograms/kg when pancuronium is given following suxamethonium. Initially, 30 to 40 micrograms/kg have been suggested in neonates, with maintenance doses of 10 to 20 micrograms/kg as necessary; in the UK, the BNFC suggests that higher doses may be used for neonates in some cases.
In the United States of America (USA), dosage based on an initial test dose of 20 micrograms/kg has been advocated for the neonate. Adult patients under intensive care who require assisted ventilation for conditions such as intractable status asthmaticus or tetanus may be given 60 micrograms/kg intravenously every 1 to 1V2 hours or less frequently.
Care should be taken when giving pancuronium to patients with hepatic or renal impairment.
Administration in Hepatic Impairment
Prolonged neuromuscular blockade may occur in patients with liver disease given pancuronium bromide since increased elimination half-life with increased volume of distribution and reduced clearance has been reported. However, the expanded distribution volume may necessitate an increase in the dose of pancuronium in these patients and may be interpreted as resistance to the neuromuscular blocking effects of pancuronium.
Administration in Renal Impairment
Prolonged neuromuscular blockade may occur when pancuronium is given to patients with severe renal impairment. Pancuronium distributes rapidly into extracellular fluid after intravenous injection, and the initial neuromuscular blockade produced will depend upon the peak drug concentration in this fluid. Since extracellular fluid volume is increased in chronic renal failure, such patients may require a larger initial dose of pancuronium. A 45% increase in dose requirement has been reported in patients with end-stage renal failure.
Renal excretion is the main route of elimination, and prolonged elimination half-life with reduced clearance may be expected in renal failure; total dose requirements may be reduced. The main infusion rate of pancuronium to maintain 90% blockade in patients with end-stage renal failure was reported to be 61.5% less than for patients with normal renal function.
Pancuronium bromide 100 micrograms/kg of the estimated fetal weight, given into the umbilical vein, produced fetal paralysis for about 40 minutes during intravascular exchange transfusion. A 200 to 300 micrograms/kg dose produced fetal paralysis for about 1 to 8 hours for more complicated transfusion procedures. No adverse effects were reported.
Neuroleptic Malignant Syndrome
Pancuronium is one of several drugs for which there have been isolated reports of success in managing neuroleptic malignant syndrome.
Adverse Effects, Treatment, and Precautions
As for competitive neuromuscular blockers in general (see Atracurium).
Pancuronium has vagolytic and sympathomimetic action, which may cause tachycardia and hypertension, but does not produce ganglionic blockade. It has little histamine-releasing effect. Hypersensitivity reactions are rare, but bradycardia, bronchospasm, hypotension, and cardiovascular collapse have been reported. Pancuronium has been associated with excessive salivation in some patients. Pancuronium should be used cautiously in patients with raised catecholamine concentrations or those receiving drugs with sympathomimetic effects, as cardiovascular adverse effects are more likely in these patients.
Effects on the Ears
A study found that neonates who survived congenital diaphragmatic hernia were more likely to suffer from sensorineural hearing loss after prolonged use of pancuronium bromide during the neonatal period. However, the authors commented that the association is not necessarily causal and that further investigation is required.
There are reports of anaphylactoid or anaphylactic reactions associated with pancuronium bromide.
Because of its prolonged duration of action, pancuronium may be more likely than other neuromuscular blockers to produce residual neuromuscular block; such residual block is associated with an increased incidence of postoperative respiratory complications.
In 15 patients undergoing cesarean section given pancuronium bromide 100 micrograms/kg intravenously with other agents, mean maternal arterial and umbilical venous serum concentrations of pancuronium bromide and metabolites were 520 and 120 nanograms/mL, respectively, at delivery (mean of 13 minutes after injection), giving a fetal to maternal ratio of 0.23.
For interactions associated with competitive neuromuscular blockers, see Atracurium.
Pharmacopoeias. In Europe, Japan, and US.
European Pharmacopoeia, 6th ed., 2008 and Supplements 6.1 and 6.2 (Pancuronium Bromide). White, yellowish-white, or slightly pink, hygroscopic crystalline powder. Very soluble to freely soluble in water; freely soluble in alcohol; very soluble in dichloromethane. Store in airtight containers. Protect from light.
The United States Pharmacopeia 31, 2008, and Supplements 1 and 2 (Pancuronium Bromide). A white, yellowish-white, or slightly pink, crystalline hygroscopic powder. Freely soluble in water, in alcohol, and in dichloromethane. Store in airtight containers at a temperature of 15° to 25°. Protect from light.
British Pharmacopoeia 2008; Pancuronium Injection.
Argentina: Bemicin; Pancuron; Pavulon; Plumger;
Brazil: Pancuron; Pavulon;
Czech Republic: Pavulon;
Hong Kong; Pavulon;
Hungary: Pavulon ;
Ireland: Pavulon ;
Mexico: Bromurex; Panlem;
The Netherlands: Pavulon;
Portugal: Pancurox; Pavulon;
South Africa: Curon-B; Pavulon;
United States of America (US and USA): Pavulon;
Venezuela: Panuron; Pavulon; Pesium.