Intramuscular Muscle relaxant in general anaesthesia
Adult: As suxamethonium Cl: 3-4 mg/kg. Max: 150 mg. Child: As suxamethonium Cl: <1 yr Up to 5 mg/kg; ≥1 yr Up to 4 mg/kg. Max: 150 mg.
Intravenous Muscle relaxant in general anaesthesia
Adult: As suxamethonium Cl: Single dose of 0.3-1.1 mg/kg by inj. Supplementary doses of 50-100% of the initial dose may be given at 5-10 min intervals. For prolonged procedures, 0.1-0.2% soln by infusion at 2.5-4 mg/min, adjusted as necessary. Max (repeated inj or continuous infusion): 500 mg/hr. Child: As suxamethonium Cl: <1 yr 2 mg/kg; 1-12 yr 1 mg/kg.
Reconstitution
Intravenous:
IV infusion: Suxamethonium Cl 1 g powd for inj or 20 mL of a soln containing 50 mg/mL may be added to 1,000 mL or 500 mL of diluent (e.g. dextrose 5%, dextrose 5% and NaCl 0.9%, NaCl 0.9%, or (1/6) M Na lactate inj) to provide a soln containing 1 mg/mL (0.1%) or 2 mg/mL (0.2%), respectively. Alternatively, suxamethonium Cl 500 mg powd for inj or 10 mL of a soln containing 50 mg/mL may be added to 500 mL or 250 mL of diluents to provide a soln containing 1 mg/mL (0.1%) or 2 mg/mL (0.2%), respectively.
Genetically determined disorders of plasma pseudocholinesterase; personal or familial history of malignant hyperthermia, myopathies associated w/ elevated serum creatine kinase values, angle-closure glaucoma, penetrating eye injuries, raised intraocular pressure; neurological deficits involving acute major muscle wasting (upper and/or lower motor neuron lesions); extensive denervation of skeletal muscle because of disease or injury to the CNS, pre-existing hyperkalaemia. Patient recovering from major trauma, extensive or severe burns.
Special Precautions
Hypersensitivity to any neuromuscular blocker. Patient w/ reduced plasma cholinesterase activity, bone fractures, neuromuscular disorders, cardiac or resp disease, electrolyte imbalance, suspected cardiac glycoside toxicity. Childn. Pregnancy and lactation.
Adverse Reactions
Prolonged resp depression or apnoea, bradycardia, tachycardia, hypotension, HTN, raised intraocular pressure, hyperkalaemia, muscle fasciculation, excessive salivation, jaw rigidity, rash. Potentially Fatal: Anaphylactic and anaphylactoid reactions, acute rhabdomyolysis w/ hyperkalaemia followed by ventricular dysrhythmias and cardiac arrest, malignant hyperthermia.
IM/IV/Parenteral: Z (Prolonged neuromuscular blockade (e.g. paralysis, apnoea, flaccidity) has been reported in mothers and neonates. Monitor for such symptoms if suxamethonium is clinically required.)
Monitoring Parameters
Monitor cardiac function and oxygenation during admin; temp, serum K and Ca, assisted ventilator status; neuromuscular function w/ peripheral nerve stimulator.
Overdosage
Symptoms: Apnoea, prolonged muscle paralysis, decreased resp reserve, low tidal vol. Management: Symptomatic and supportive treatment. Maintain airway and adequate ventilation until recovery of normal respiration is assured. Use of neostigmine to reverse a non-depolarising suxamethonium-induced block should be accompanied by appropriate doses of an anticholinergic agent (e.g. atropine).
Description: Mechanism of Action: Suxamethonium Cl is an ultrashort-acting depolarising type skeletal muscle relaxant. It blocks the neuromuscular junction by binding to the cholinergic receptors and depolarising it. Onset: 0.5-1 min (IV); approx 2-3 min (IM). Duration: 4-6 min (IV); 10-30 min (IM). Pharmacokinetics: Distribution: Crosses the placenta (small amounts). Metabolism: Rapidly hydrolysed by plasma cholinesterase. Excretion: Via urine, approx 10% as unchanged drug.
Chemical Structure
Suxamethonium Source: National Center for Biotechnology Information. PubChem Database. Succinylcholine, CID=5314, https://pubchem.ncbi.nlm.nih.gov/compound/Succinylcholine (accessed on Jan. 23, 2020)
Anon. Succinylcholine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 29/10/2015.Buckingham R (ed). Suxamethonium Chloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. http://www.medicinescomplete.com. Accessed 29/10/2015.Joint Formulary Committee. Suxamethonium Chloride. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. http://www.medicinescomplete.com. Accessed 29/10/2015.McEvoy GK, Snow EK, Miller J et al (eds). Succinylcholine Chloride. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). http://www.medicinescomplete.com. Accessed 29/10/2015.Quelicin Succinylcholine Chloride Injection, Solution (Hospira, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 29/10/2015.
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