Suxamethonium Chloride (Succinylcholine)

Indications

Suxamethonium Chloride (Succinylcholine) is used for: Muscle relaxant

Adult Dose

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. Intramuscular Muscle relaxant in general anaesthesia Adult: As suxamethonium Cl: 3-4 mg/kg. Max: 150 mg.

Child Dose

Intravenous Muscle relaxant in general anaesthesia Child: As suxamethonium Cl: <1 yr 2 mg/kg; 1-12 yr 1 mg/kg. Intramuscular Muscle relaxant in general anaesthesia Child: As suxamethonium Cl: <1 yr Up to 5 mg/kg; >1 yr Up to 4 mg/kg. Max: 150 mg.

Renal Dose

Administration

Reconstitution: 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.

Contra Indications

Genetic disorders of plasma pseudocholinesterase, personal/family history of malignant hyperthermia, hypersensitivity from previous neuromuscular drug, severe burns, massive trauma, extensive denervation of skeletal muscle, patients with risk of hyperkalaemia, renal impairment, angle closure glaucoma.

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. Monitoring Parameters Monitor cardiac function and oxygenation during admin; temp, serum K and Ca, assisted ventilator status; neuromuscular function w/ peripheral nerve stimulator.

Pregnancy-Lactation

Pregnancy Not known whether succinylcholine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity; animal reproduction studies not conducted with succinylcholine chloride; therapy should be administered to a pregnant woman only if clearly needed Labor and delivery Drug is commonly used to provide muscle relaxation during delivery by Cesarean section; while small amounts of succinylcholine are known to cross placental barrier, under normal conditions the quantity of drug that enters fetal circulation after a single dose of 1 mg/kg to mother should not endanger fetus; however, since amount of drug that crosses the placental barrier is dependent on concentration gradient between maternal and fetal circulations, residual neuromuscular blockade (apnea and flaccidity) may occur in the neonate after repeated high doses to, or in the presence of atypical plasma cholinesterase in, the mother Lactation Not known whether drug excreted in human milk; because many drugs are excreted in human milk, use caution following succinylcholine administration to a nursing woman

Interactions

Prolonged neuromuscular blocking effects w/ specific anticholinesterase agents (e.g. neostigmine), cytotoxic compd (e.g. cyclophosphamide), antiarrhythmics (e.g. quinidine), aminoglycosides, psychiatric drugs (e.g. chlorpromazine), Mg salts, anaesth agents (e.g. morphine), SSRIs, organophosphate insecticides. Increased susceptibility to the effects of suxamethonium-exacerbated hyperkalaemia w/ digitalis-like drugs.

Adverse Effects

Side effects of Suxamethonium Chloride (Succinylcholine) : 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.

Mechanism of Action

Suxamethonium chloride is an ultrashort-acting depolarising type skeletal muscle relaxant. It blocks the neuromuscular junction by binding to the cholinergic receptors and depolarising it.