PANURON

Indications

• Facilitation of tracheal intubation
• Skeletal muscle relaxation during surgery
• Management of mechanical ventilation

Dosage

Children: For children, the initial dose is usually 0.1 to 0.

Adults: The initial dose for adults is typically 0.08 to 0.12 mg/kg, with maintenance doses of 0.01 to 0.05 mg/kg as needed based on clinical response.

Mechanism of action

Pancuronium inhibits neuromuscular transmission by competing with acetylcholine for the cholinergic receptors at the motor end plate. This competitive antagonism reduces the response of the end plate to acetylcholine, leading to muscle paralysis. The neuromuscular block induced by pancuronium can be reversed by anticholinesterase agents.

Pharmacodynamics

Pancuronium is a non-depolarizing muscle relaxant that functions as a competitive antagonist at the post-synaptic nicotinic acetylcholine receptors located at the neuromuscular junction. Unlike depolarizing agents such as suxamethonium, pancuronium does not cause spontaneous depolarizations or muscle fasciculations. It exhibits slight vagolytic activity, which can lead to an increase in heart rate due to reduced vagal tone, but it does not have ganglioplegic activity.

Pharmacokinetics

Pancuronium is administered intravenously and has a relatively long duration of action compared to other muscle relaxants. It is metabolized primarily in the liver, and its metabolites are excreted in the urine. The onset of action typically occurs within 2 to 4 minutes, and the effects can last for 60 to 90 minutes, depending on the dose. Factors such as renal function can influence the duration of action, as impaired renal clearance can prolong neuromuscular blockade.

Interactions

• pancuronium + digoxin: Unknown (increases risk of cardiovascular adverse effects)

Pregnancy

Pancuronium should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Pancuronium is not recommended during breastfeeding due to the potential for adverse effects in the infant.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Indications

• Neuromuscular blockade during surgery
• Facilitation of intubation
• Neuromuscular blockade in intensive care settings

Dosage

Children: Child 2–5 months: Initially 150 micrograms/kg, then 100 micrograms/kg every 6–9 minutes as required; alternatively, 8–10 micrograms/kg/minute by continuous intravenous infusion.

Adults: Initially 100 micrograms/kg intravenously, then 60 micrograms/kg every 60–90 minutes as required.

Mechanism of action

Pancuronium bromide acts as a competitive antagonist at the neuromuscular junction by binding to nicotinic acetylcholine receptors on the motor end plate, inhibiting the action of acetylcholine. This blockade prevents muscle contraction, leading to paralysis. The effect is dose-dependent and can be reversed by cholinesterase inhibitors like neostigmine.

Pharmacodynamics

Pancuronium bromide has a long duration of action compared to other neuromuscular blockers. Its onset of action is relatively rapid, but the duration can last from 60 to 90 minutes. The drug is devoid of histamine-releasing properties, which minimizes the risk of hypotension. However, it can cause tachycardia due to its vagolytic effects.

Pharmacokinetics

Pancuronium is primarily eliminated by renal excretion, with a significant portion excreted unchanged in the urine. The half-life varies based on factors such as renal function and patient condition, but it generally ranges from 1 to 2 hours. In patients with renal impairment, the duration of neuromuscular blockade may be prolonged, necessitating careful monitoring and potential dose adjustments.

Contra-indications

• Hypersensitivity to pancuronium bromide
• Neuromuscular disease
• Severe cardiovascular disease
• Sensitivity to reduced arterial blood pressure

Adverse effects

• Apnoea
• Hypersalivation
• Tachycardia
• Increased cardiac output
• Malignant hyperthermia
• Prolonged neuromuscular blockade
• Arrhythmia

Interactions

• Other neuromuscular blocking agents
• Aminoglycoside antibiotics (may potentiate effects)
• Calcium channel blockers (may potentiate effects)
• Antibiotics such as tetracyclines and clindamycin (may potentiate effects)

Precautions

• Use with caution in patients with hepatic impairment (may require dose adjustment)
• Use with caution in patients with renal impairment (may prolong duration of block)
• Monitor closely in obese patients (dose should be calculated on ideal body weight)

Pregnancy

Pancuronium bromide should be used with caution during pregnancy, as safety in human pregnancy has not been established.

Breast-feeding

It is unknown whether pancuronium bromide is excreted in human milk; caution is advised when administering to breastfeeding patients.

Storage

Store in a cool, dry place, protected from light. Do not freeze.

Formulations

• Pancuronium bromide 2 mg/ml solution for injection
• Pancuronium bromide 20 mg/10 ml solution for injection

Mechanism of action

Nondepolarizing neuromuscular blocking agents inhibit neuromuscular transmission by competing with acetylcholine for the cholinergic receptors of the motor end plate, thereby reducing the response of the end plate to acetylcholine. This type of neuromuscular block is usually antagonized by anticholinesterase agents.

Pharmacodynamics

Pancuronium is a non-depolarising muscle relaxant similar to curare. It acts as a competitive acetylcholine antagonist on neuromuscular junctions, displacing acetylcholine (hence competitive) from its post-synaptic nicotinic acetylcholine receptors. It is, unlike suxamethonium, a non-depolarising agent, which means, that it causes no spontaneous depolarisations upon association with the nicotinic receptor in neuromuscular junction, thus producing no muscle fasciculations upon administration. Pancuronium has no hormonal activity. It exerts slight vagolytic activity (i.e. diminishing activity of the vagus nerve) and no ganglioplegic (i.e., blocking ganglions) activity.