Pancuronium Bromide
Pancuronium bromide is a **non-depolarizing neuromuscular blocking agent** primarily used as an adjunct to general anesthesia. It provides skeletal muscle relaxation to facilitate **endotracheal intubation**, **mechanical ventilation**, and various surgical procedures. > **CRITICAL CLINICAL NOTE**: Pancuronium possesses **NO analgesic, sedative, or amnestic properties**. Patients must be adequately sedated and anesthetized before and during its use to prevent the terrifying experience of being paralyzed while conscious. * It is a long-acting aminosteroid muscle relaxant. * Compared to other agents, it has a relatively long duration of action (30-45 minutes depending on dose) and relies heavily on renal excretion. * It is considered 5 times as potent as d-tubocurarine and approximately ⅓ as potent as vecuronium (though some sources suggest equipotency in animals).
Mecanismo: Pancuronium acts as a competitive antagonist at the **nicotinic acetylcholine receptors (nAChRs)** located at the **neuromuscular junction (motor endplate)**. * Pancuronium competitively binds to **nAChRs** → prevents **acetylcholine (ACh)** from binding → inhibits depolarization of the muscle fiber membrane → results in flaccid skeletal muscle paralysis. * **Cardiovascular Effects**: Unlike some other neuromuscular blockers, pancuronium has slight vagolytic (anticholinergic) activity at postganglionic **muscarinic receptors** in the heart → leads to slight increases in heart rate and blood pressure. * It rarely causes histamine release compared to older agents like d-tubocurarine.
Dosificación por especie
- General muscle relaxation · 0.044-0.11 mg/kg IV · IV · as needed · higher dose used initially; lower doses required if repeated doses are necessary
- Neuromuscular blockade during anaesthesia · 0.025-0.075 mg/kg initially; repeat doses at increments of 0.01 mg/kg · IV · as needed · Duration of action >45 min · Initially use a higher dose. Repeated doses may be cumulative and lead to difficulty in antagonism.
- Muscle relaxation · 0.1 mg/kg IV · IV · as needed · Dose for rabbits
- As a paralytic during mechanical ventilation · 0.05-0.1 mg/kg IV · IV · lasts about an hour · must give sedation as well
- General muscle relaxation · 0.044-0.11 mg/kg IV · IV · as needed · higher dose used initially; lower doses required if repeated doses are necessary
- Anesthesia maintenance adjunct (when inhalational agents result in severe hypotension) · 0.02-0.04 mg/kg IV · IV · provides 30-45 minutes of muscle relaxation · Used when IV/regional techniques are inadequate to prevent spontaneous movement
- Neuromuscular blockade during anaesthesia · 0.025-0.075 mg/kg initially; repeat doses at increments of 0.01 mg/kg · IV · as needed · Duration of action >45 min · Initially use a higher dose. Repeated doses may be cumulative and lead to difficulty in antagonism.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Known hypersensitivity to pancuronium or bromides
- Myasthenia gravis (extreme caution or contraindicated)
- Conscious or inadequately anaesthetized animals
- Lack of positive pressure ventilation facilities
- Lack of monitoring equipment (nerve stimulator)
Efectos adversos
- Slight elevations in cardiac rate and blood pressure
- Hypersalivation (if not pretreated with an anticholinergic agent)
- Prolonged or profound muscular weakness
- Respiratory depression
- Histamine release with resultant hypersensitivity reaction (Very Rare)
- Tachycardia (due to vagolytic effect)
- Prolonged neuromuscular blockade
- Mild hypertension
Interacciones farmacológicas
- Azathioprine · May reverse pancuronium's neuromuscular blocking effects
- Aminoglycosides (e.g., gentamicin) · May enhance the neuromuscular blocking activity of pancuronium
- Calcium (IV) · May reverse the effects of nondepolarizing neuromuscular blocking agents
- Lincosamides (e.g., clindamycin) · May enhance the neuromuscular blocking activity of pancuronium
- Magnesium sulfate or HCl · May enhance the neuromuscular blocking activity of pancuronium
- Quinidine · May enhance the neuromuscular blocking activity of pancuronium
- Succinylcholine · May speed the onset of action and enhance the neuromuscular blocking actions of pancuronium. Do not give pancuronium until succinylcholine effects have subsided.
- Theophylline · May inhibit or reverse the neuromuscular blocking action of pancuronium and possibly induce arrhythmias
- Tricyclic Antidepressants (e.g., clomipramine, amitriptyline) · Increased risk for cardiac arrhythmias when used with halothane anesthesia
- Volatile anaesthetics · Prolonged neuromuscular blockade · moderate
- Aminoglycosides · Prolonged neuromuscular blockade · major
- Clindamycin · Prolonged neuromuscular blockade · moderate
Monitorización
- Level of neuromuscular blockade (via peripheral nerve stimulation)
- Cardiac rate and rhythm
- Blood pressure
- Adequacy of ventilation and oxygenation
- Peripheral nerve stimulation (e.g., Train-of-Four)
- Heart rate and rhythm
- Respiratory rate, effort, and ventilator parameters (EtCO2, SpO2)
- Body temperature
- Acid-base status
- Serum potassium levels
Sobredosis
Overdosage increases the risk of **hypotension**, **histamine release**, and **prolonged duration of muscle blockade**. **Treatment:** * **Conservative Support**: Maintain mechanical ventilation, oxygen therapy, and IV fluids until spontaneous breathing returns. * **Pharmacologic Reversal**: Blockade may be reversed by administering an **anticholinesterase agent** (e.g., edrophonium, physostigmine, or neostigmine). * **CRITICAL**: An **anticholinergic** (atropine or glycopyrrolate) MUST be administered prior to or alongside the reversal agent to prevent severe bradycardia and muscarinic side effects. * *Suggested Reversal Protocol*: **Neostigmine** 0.06 mg/kg IV *after* **Atropine** 0.02 mg/kg IV.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.