G-Suxamethonium

• Approved Indications:
• Facilitation of endotracheal intubation during general anesthesia.
• Rapid sequence induction requiring brief skeletal muscle relaxation.
• Adjunct to general anesthesia to achieve muscle relaxation for surgical or diagnostic procedures.
• Facilitation of mechanical ventilation in critically ill patients requiring muscle paralysis.
• Off-label Uses:
• Muscle relaxation during electroconvulsive therapy (ECT) to prevent musculoskeletal injury.

• Adults:
• Recommended dose for rapid sequence intubation is 1 mg/kg intravenously.
• Onset of action occurs within 30 to 60 seconds, with muscle relaxation lasting approximately 4 to 6 minutes.
• Repeated dosing is generally avoided due to the risk of prolonged paralysis.
• Pediatrics:
• Dose ranges from 1 to 1.5 mg/kg intravenously.
• Elderly:
• Dose adjustments may be necessary because of increased sensitivity and reduced metabolism.
• Hepatic and Renal Impairment:
• Use with caution; metabolism may be prolonged in patients with impaired plasma cholinesterase activity.
• Route of Administration:
• Administered by intravenous injection or infusion only.
• Monitoring:
• Continuous monitoring of respiratory and cardiovascular function is essential during administration.

Suxamethonium chloride is a depolarizing neuromuscular blocking agent. It acts as an acetylcholine receptor agonist at the neuromuscular junction, causing persistent depolarization of the motor endplate. This sustained depolarization prevents repolarization, rendering the muscle fibers unable to respond to subsequent nerve impulses, leading to transient muscle fasciculations followed by flaccid paralysis. The drug’s action is terminated by hydrolysis through plasma cholinesterase.

• Absorption: Administered intravenously with immediate bioavailability.
• Distribution: Rapidly distributes to neuromuscular junctions; negligible plasma protein binding.
• Metabolism: Rapid hydrolysis by plasma pseudocholinesterase (butyrylcholinesterase).
• Elimination: Metabolites are primarily excreted in the urine.
• Onset of Action: 30–60 seconds after intravenous administration.
• Duration of Effect: Approximately 4 to 6 minutes.

• Pregnancy: Classified as FDA Pregnancy Category C. Animal studies have shown adverse effects at high doses; there are no adequate, well-controlled studies in humans. Use only if the potential benefits justify the risks.
• Lactation: It is not known whether suxamethonium is excreted in human breast milk. Use with caution during breastfeeding, weighing potential benefits against possible risks.
• Data: Limited human data available for pregnancy and lactation.

• Primary Therapeutic Class: Neuromuscular blocking agent.
• Subclass: Depolarizing muscle relaxant.

• Known hypersensitivity to suxamethonium or any component of the formulation.
• Personal or family history of malignant hyperthermia.
• Atypical plasma cholinesterase or known pseudocholinesterase deficiency.
• Severe burns (>24 hours post-injury), major trauma, or muscle denervation (due to risk of severe hyperkalemia).
• Pre-existing hyperkalemia.
• Penetrating eye injuries (relative contraindication).
• Narrow-angle glaucoma (relative contraindication).

• Hyperkalemia Risk: Can cause severe hyperkalemia, particularly in patients with burns, trauma, neuromuscular diseases, or prolonged immobilization.
• Malignant Hyperthermia: Can trigger this potentially fatal reaction; ensure readiness for immediate treatment.
• Cardiac Effects: Bradycardia and asystole may occur, especially with repeated doses or in pediatric patients; atropine may be used prophylactically.
• Prolonged Apnea: Possible in patients with atypical plasma cholinesterase variants.
• Increased Intraocular and Intracranial Pressure: Use with caution in patients with eye trauma or increased intracranial pressure.
• Histamine Release: Rarely, may cause hypotension or bronchospasm.
• Continuous monitoring of respiratory and cardiovascular function is essential during use.

• Common:
• Muscle fasciculations immediately after injection.
• Postoperative muscle pain or stiffness.
• Bradycardia or tachycardia.
• Serious but Rare:
• Life-threatening hyperkalemia leading to cardiac arrest.
• Malignant hyperthermia.
• Anaphylactic reactions or hypersensitivity.
• Prolonged paralysis in individuals with atypical plasma cholinesterase.
• Raised intraocular pressure.
• Increased intragastric pressure.

• Cholinesterase Inhibitors: Prolong duration of paralysis by inhibiting metabolism.
• Aminoglycosides and Tetracyclines: May enhance neuromuscular blockade.
• Volatile Anesthetics: Increase risk of malignant hyperthermia when used concurrently.
• Beta-blockers and Calcium Channel Blockers: May increase risk of bradycardia.
• Magnesium Sulfate: Potentiates neuromuscular blockade.
• Avoid concomitant use with drugs that reduce plasma cholinesterase activity to prevent prolonged paralysis.

• Screening for malignant hyperthermia susceptibility is emphasized prior to use.
• Avoidance of suxamethonium in patients at risk of hyperkalemia has been strongly recommended in recent anesthesia guidelines due to potential fatal arrhythmias.
• Non-depolarizing neuromuscular blockers are preferred for prolonged muscle relaxation or in high-risk patients.
• Updated protocols stress continuous monitoring and emergency preparedness during administration.

• Store at controlled room temperature: 20°C to 25°C (68°F to 77°F).
• Protect from light; keep medication in original container until use.
• Avoid freezing.
• Maintain sterility after vial puncture; discard unused portions promptly.
• Keep out of reach of children.