Usage
- Pancuronium bromide is a non-depolarizing neuromuscular blocking agent used as an adjunct to general anesthesia to facilitate tracheal intubation and provide skeletal muscle relaxation during surgery or mechanical ventilation. It is also used to facilitate management of patients undergoing mechanical ventilation in the ICU.
- Pharmacological Classification: Neuromuscular blocking agent, non-depolarizing.
- Mechanism of Action: Pancuronium competitively blocks the action of acetylcholine at the postsynaptic nicotinic cholinergic receptors at the neuromuscular junction, preventing depolarization and subsequent muscle contraction.
Alternate Names
- Pancuronium bromide
- Brand Names: Pavulon
How It Works
- Pharmacodynamics: Pancuronium produces skeletal muscle paralysis by competing with acetylcholine for nicotinic cholinergic receptors at the neuromuscular junction. This action is readily reversed by acetylcholinesterase inhibitors such as neostigmine or edrophonium. The cardiovascular effects are generally modest and transient, and may include a slight increase in heart rate and blood pressure. Pancuronium does not possess analgesic or anesthetic properties.
- Pharmacokinetics: Pancuronium is administered intravenously. Onset of action occurs within 2 to 3 minutes, and the duration of effect ranges from 60 to 90 minutes following an initial dose. Supplemental doses have a longer duration of action due to cumulative effects. It is primarily excreted unchanged by the kidneys, with some hepatic metabolism. The clearance is reduced in renal impairment.
- Mode of Action: Competitive antagonism of acetylcholine at nicotinic cholinergic receptors at the motor endplate.
- Receptor Binding: Binds to nicotinic cholinergic receptors at the neuromuscular junction.
- Elimination Pathways: Primarily renal excretion (approximately 60-80%), with some hepatic metabolism.
Dosage
Standard Dosage
Adults:
- Initial dose: 0.04-0.1 mg/kg IV.
- Maintenance dose: 0.01-0.015 mg/kg IV every 20-60 minutes as needed, or continuous infusion of 0.02-0.04 mg/kg/hr.
- For intubation: 0.06-0.1 mg/kg IV bolus.
Children:
- Neonates (<28 days old): Initial dose: 0.02 mg/kg IV; maintenance dose: 0.05-0.1 mg/kg every 30 minutes to 4 hours or as needed.
- Infants and Children (>1 month old): Similar dosing as adults. Initial dose: 0.04-0.1 mg/kg IV; maintenance dose: 0.01-0.015 mg/kg IV every 20-60 minutes or as needed, or continuous infusion of 0.1mg/kg/hr IV.
Special Cases:
- Elderly Patients: Dose adjustment may be necessary due to potential age-related decline in renal function. Close monitoring is recommended.
- Patients with Renal Impairment: Reduce dosage or avoid use in severe renal impairment (creatinine clearance <10 mL/min). For creatinine clearance 10-50 mL/min, administer 50% of the usual dose.
- Patients with Hepatic Dysfunction: Use with caution. Dose adjustment may be necessary. Monitor closely for prolonged effect.
- Patients with Comorbid Conditions: Consider potential drug interactions and dose adjustments.
Clinical Use Cases
- Intubation: 0.06-0.1 mg/kg IV bolus.
- Surgical Procedures: 0.04-0.1 mg/kg IV initial dose, followed by maintenance doses.
- Mechanical Ventilation: 0.06 mg/kg/hr IV infusion, titrated to effect.
- Intensive Care Unit (ICU) Use: Continuous infusion, titrated to achieve desired level of paralysis. Consider “drug holidays” to assess the continued need for neuromuscular blockade.
- Emergency Situations: Initial dose: 0.06-0.1 mg/kg IV bolus.
Dosage Adjustments
- Renal impairment: Reduce dosage or avoid use in severe renal impairment.
- Hepatic impairment: Use with caution, and adjust dosage as needed based on patient response and duration of effect.
Side Effects
Common Side Effects
- Flushing
- Increased salivation
- Mild tachycardia and hypertension
- Rash
Rare but Serious Side Effects
- Bronchospasm
- Hypersensitivity reactions (including anaphylaxis)
- Prolonged paralysis
- Hypotension
- Bradycardia
Long-Term Effects
- Muscle weakness (with prolonged use)
Adverse Drug Reactions (ADR)
- Anaphylaxis
- Prolonged apnea
Contraindications
- Hypersensitivity to pancuronium or bromide ion
- Myasthenia gravis or other neuromuscular disorders
- Patients for whom a minor increase in heart rate would be harmful (e.g. some cardiac conditions)
Drug Interactions
- Inhalational anesthetics (halothane, isoflurane, enflurane): Potentiate neuromuscular blockade.
- Aminoglycoside antibiotics, other non-depolarizing neuromuscular blockers, magnesium salts: Enhance neuromuscular blockade.
- Depolarizing neuromuscular blockers (succinylcholine): Initial dose of pancuronium should be reduced if administered after succinylcholine.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: C. Use only if potential benefit outweighs potential risk to the fetus.
- Breastfeeding: No specific data available. Use caution. The drug is highly polar and poorly absorbed orally, making significant transfer to breast milk unlikely.
Drug Profile Summary
- Mechanism of Action: Competitive inhibitor of acetylcholine at nicotinic cholinergic receptors at the neuromuscular junction.
- Side Effects: Flushing, increased salivation, tachycardia, hypertension, rash, bronchospasm, prolonged paralysis, hypersensitivity reactions.
- Contraindications: Hypersensitivity to pancuronium or bromide, myasthenia gravis.
- Drug Interactions: Inhalational anesthetics, aminoglycosides, magnesium salts, other neuromuscular blockers.
- Pregnancy & Breastfeeding: Category C; use with caution in breastfeeding.
- Dosage: Adults: 0.04-0.1 mg/kg IV initial; children: similar to adults.
- Monitoring Parameters: Heart rate, blood pressure, respiratory rate, neuromuscular function (peripheral nerve stimulator).
Popular Combinations
- Commonly used with inhalational anesthetics and other components of general anesthesia.
Precautions
- General Precautions: Monitor neuromuscular function, respiratory status, and cardiovascular parameters closely. Ensure availability of reversal agents (neostigmine, atropine) and ventilation support. Adjust dosage for patients with renal or hepatic impairment.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Pancuronium?
A: The initial dose for adults and children >1 month is 0.04-0.1 mg/kg IV, with maintenance doses of 0.01-0.015 mg/kg as needed or a continuous infusion. For neonates <28 days old, the initial dose is 0.02 mg/kg IV with a maintenance dose of 0.05-0.1 mg/kg. Dosage should be adjusted in renal impairment.
Q2: How does Pancuronium work?
A: Pancuronium competitively inhibits acetylcholine at nicotinic receptors at the neuromuscular junction, resulting in muscle paralysis.
Q3: What are the common side effects?
A: Common side effects include flushing, increased salivation, tachycardia, and mild hypertension.
Q4: What are the serious side effects?
A: Serious side effects include bronchospasm, hypersensitivity reactions, and prolonged paralysis.
Q5: What are the contraindications for using Pancuronium?
A: Contraindications include hypersensitivity to the drug, myasthenia gravis, and other neuromuscular disorders.
Q6: Does Pancuronium interact with other medications?
A: Yes, Pancuronium interacts with several medications, including inhalational anesthetics, aminoglycosides, and magnesium salts, which can enhance its effects.
Q7: Can Pancuronium be used in pregnant or breastfeeding women?
A: Pancuronium is a Pregnancy Category C drug, meaning it should be used only if the potential benefit justifies the potential risk to the fetus. Limited data are available regarding its use during breastfeeding.
Q8: How is Pancuronium reversed?
A: Neuromuscular blockade induced by pancuronium can be reversed using acetylcholinesterase inhibitors, such as neostigmine or edrophonium, often in combination with atropine to counteract muscarinic side effects.
Q9: How should Pancuronium be monitored?
A: Closely monitor heart rate, blood pressure, respiratory rate, and neuromuscular function (via peripheral nerve stimulator).
Q10: What are special considerations for elderly patients?
A: Elderly patients may have reduced renal function. Closely monitor and adjust the dose as necessary.
