Medically reviewed by Drugs.com. Last updated on Apr 12, 2020.
(suks in il KOE leen)
- Succinylcholine Chloride
- Suxamethonium Chloride
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Injection, as chloride:
Anectine: 20 mg/mL (10 mL) [contains methylparaben]
Quelicin: 20 mg/mL (10 mL) [contains methylparaben, propylparaben]
Generic: 20 mg/mL (10 mL)
Brand Names: U.S.
- Neuromuscular Blocker Agent, Depolarizing
Acts similar to acetylcholine, produces depolarization of the motor endplate at the myoneural junction which causes sustained flaccid skeletal muscle paralysis produced by state of accommodation that develops in adjacent excitable muscle membranes
Vd higher in neonates and infants due to larger ECF volume; higher IV doses necessary
Rapidly hydrolyzed by plasma pseudocholinesterase to inactive metabolites
Urine (~10% excreted unchanged)
Onset of Action
Dependent on route, age, and dose; data suggest faster onset with higher doses (Coté 2013):
IM: Infants and Children: 3 to 4 minutes (Liu 1981); Adults: 2 to 3 minutes
Neonates and Infants: ~30 seconds (range: 19 to 40 seconds [dose: 2 to 4 mg/kg]) (Meakin 1990)
Children and Adolescents: 35 to 55 seconds (Coté 2013); Dose-specific: 40 seconds (dose: 1.5 to 2 mg/kg); 50 seconds (dose: 1 mg/kg) (Coté 2013)
Adults: Flaccid paralysis rapid <60 seconds
Duration of Action
Dependent on route, age, and dose; hypothermia may prolong the duration of action:
IM: 10 to 30 minutes; observed to be shorter in infants than children
IV: ~4 to 6 minutes; faster recovery rate in infants and children compared to adults (Fisher 1975)
Use: Labeled Indications
Neuromuscular blockade for endotracheal intubation, surgery, or mechanical ventilation: As an adjunct to general anesthesia to facilitate tracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation in adequately sedated patients
Note: Neuromuscular blockade does not provide pain control, sedation, or amnestic effects. Appropriate analgesic and sedative mediations should be used before and during administration of neuromuscular blockade to achieve deep sedation.
Off Label Uses
Electroconvulsive therapy, muscle relaxation
Data from a limited number of patients studied suggest that succinylcholine may be beneficial to minimize muscle contractions during electroconvulsive therapy [Mirzakhani 2016], [Murali 1999].
Hypersensitivity to succinylcholine or any component of the formulation; personal or familial history of malignant hyperthermia; skeletal muscle myopathies; use after the acute phase of injury following major burns, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury.
Documentation of allergenic cross-reactivity for neuromuscular blockers is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.
Note: Dose to effect; doses will vary due to interpatient variability. Ensure adequate pain control and sedation prior to and during administration of neuromuscular blockade. Use carefully and/or consider dose reduction in patients with reduced plasma cholinesterase activity due to genetic abnormalities of plasma cholinesterase or when associated with other conditions (eg, electrolyte abnormalities, neuromuscular disease); prolonged neuromuscular blockade may occur.
Electroconvulsive therapy (ECT), muscle relaxation (off-label use): IV: 0.5 to 1.5 mg/kg (doses ≥0.75 mg/kg are more common in clinical practice); adjust dose higher or lower based on muscle mass, muscle relaxation with previous ECT, and patient-specific risks associated with suboptimal relaxation (eg, increase dose in patients with osteoporosis) (Ding 2002; Mirzakhani 2016; Murali 1999). Note: Most patients will recover respiratory function and muscle strength within 9 to 10 minutes (Mirzakhani 2016; Murali 1999).
Neuromuscular blockade for endotracheal intubation, surgery, or mechanical ventilation (as adjunct to general anesthesia):
IM: Up to 3 to 4 mg/kg, maximum total dose: 150 mg.
Intubation: 0.6 mg/kg (range: 0.3 to 1.1 mg/kg).
Rapid-sequence intubation (off-label dosing): 1 to 1.5 mg/kg (Sluga 2005; Weiss 1997).
Long surgical procedures (intermittent administration): Initial: 0.3 to 1.1 mg/kg; administer 0.04 to 0.07 mg/kg at appropriate intervals as needed.
Note: Pretreatment with atropine may reduce occurrence of bradycardia. Initial dose of succinylcholine must be increased when nondepolarizing agent pretreatment is used because of the antagonism between succinylcholine and nondepolarizing neuromuscular-blocking agents (Miller 2010). When the cumulative dose of succinylcholine exceeds 2 to 4 mg/kg under general anesthesia, transition from a phase I to a phase II block may occur. If phase II block is suspected, diagnosis should be confirmed by peripheral nerve stimulation prior to administration of an anticholinesterase drug (Hilgenberg 1981).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Refer to adult dosing.
Note: Dose to effect; doses will vary due to interpatient variability. Use carefully and/or consider dose reduction in patients with reduced plasma cholinesterase activity due to genetic abnormalities of plasma cholinesterase or when associated with other conditions (eg, electrolyte abnormalities, neuromuscular disease); prolonged neuromuscular blockade may occur. Initial dose of succinylcholine must be increased when nondepolarizing agent pretreatment used because of the antagonism between succinylcholine and nondepolarizing neuromuscular-blocking agents (Miller 2010). Because of the risk of adverse effects including malignant hyperthermia and cardiac arrhythmias, surgical or long-term paralytic use (ie, continuous IV infusion) is not recommended (Coté 2013; Fisher 1999).
Endotracheal intubation; emergent (eg, rapid sequence intubation): Note: To reduce the risk of bradycardia or asystole, premedication with atropine recommended prior to IV succinylcholine doses (AAP [Hegenbarth 2008]; Coté 2013)
Infants, Children, and Adolescents: Note: In obese patients, pediatric patient data (age range: 9 to 15 years) suggest dosing based on use total body weight (Rose 2000).
Infants <6 months: Limited data available: 4 to 5 mg/kg; pharmacokinetic data suggests that young infants typically require doses on the higher end of this range (AAP [Hegenbarth 2008]; Coté 2013)
Infants ≥6 months and Children: 4 mg/kg; maximum dose: 150 mg/dose (AAP [Hegenbarth 2008]; Lui 1981)
Adolescents: 3 to 4 mg/kg; maximum dose: 150 mg/dose
Infants ≤6 months: 2 to 3 mg/kg/dose
Infants >6 months and Children ≤2 years: 1 to 2 mg/kg/dose
Children >2 years and Adolescents: 1 mg/kg/dose
Alternate dosing: Limited data available:
Infants: 2 to 3 mg/kg/dose (AAP [Hegenbarth 2008]; Coté 2013)
Children: 1 to 2 mg/kg/dose (AAP [Hegenbarth 2008]; Ballow 2012; Coté 2013)
Adolescents: 1 to 1.5 mg/kg/dose (Ballow 2012; Sluga 2005; Weiss 1997)
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
The recommendations for dosing in obese patients are based upon the best available evidence and clinical expertise. Senior Editorial Team: Jeffrey F. Barletta, PharmD, FCCM; Manjunath P. Pai, PharmD, FCP; Jason Roberts, PhD, BPharm (Hons), B App Sc, FSHP, FISAC.
Principles of body weight dosing:
Data evaluating succinylcholine dosing in extreme obesity originate from studies conducted in the surgery setting (Bentley 1982; Lemmens 2006; Rose 2000). In one study with healthy subjects, a positive correlation was noted between pseudocholinesterase activity and body surface area, weight, and BMI. A similar duration of effect was observed for succinylcholine doses based on actual body weight, regardless of weight, after 1 mg/kg was administered (Bentley 1982). A retrospective cohort study suggests obese patients (≥120 kg) received a sub-optimal dose (≤1 mg/kg) and subsequently had decreased first pass success with rapid sequence intubation in the emergency department (Patanwala 2017). A randomized controlled trial evaluating succinylcholine weight-based dosing found use of actual body weight resulted in more favorable intubating conditions compared to using ideal body weight (IBW) or lean body weight (Lemmens 2006).
IV, IM: Use actual body weight for weight-based dosing in obese patients (Lemmens 2006). In patients with extreme obesity (eg, BMI >60 kg/m2), consider using 40% adjusted body weight (AdjBW) for weight-based dosing calculations; however, intubating conditions may be less than optimal (expert opinion).
AdjBW = [0.4 × (total body weight – IBW) + IBW].
IM: Administer deep IM only when IV access is not available.
IV: May be administered undiluted by rapid IV injection.
Manufacturer recommends refrigeration at 2°C to 8°C (36°F to 46°F) and may be stored at room temperature for 14 days; however, additional testing has demonstrated stability for ≤6 months unrefrigerated (25°C) (Ross 1988; Roy 2008). Stability in polypropylene syringes (20 mg/mL) at room temperature (25°C) is 45 days (Storms 2003). According to the 2020 to 2021 ISMP Targeted Medication Safety Best Practices for Hospitals, neuromuscular blockers should be segregated, sequestered, and differentiated from all other medication wherever they are stored (ISMP 2020).
Acetylcholinesterase Inhibitors: May increase the serum concentration of Succinylcholine. Management: Consider alternatives to this combination due to a risk of prolonged neuromuscular blockade. Consider therapy modification
Aminoglycosides: May enhance the therapeutic effect of Neuromuscular-Blocking Agents. Monitor therapy
Bacitracin (Systemic): May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Bambuterol: May enhance the therapeutic effect of Succinylcholine. Bambuterol may increase the serum concentration of Succinylcholine. Monitor therapy
Botulinum Toxin-Containing Products: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Bromperidol: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Capreomycin: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Cardiac Glycosides: Neuromuscular-Blocking Agents may enhance the arrhythmogenic effect of Cardiac Glycosides. Monitor therapy
Clindamycin (Topical): May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Colistimethate: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Management: If possible, avoid concomitant use of these products. Monitor for deeper, prolonged neuromuscular-blocking effects (respiratory paralysis) in patients receiving concomitant neuromuscular-blocking agents and colistimethate. Consider therapy modification
Cyclophosphamide: May increase the serum concentration of Succinylcholine. Management: Consider alternatives to succinylcholine in patients who have received cyclophosphamide in the past 10 days, or reduced succinylcholine doses (a serum pseudocholinesterase assay may help inform this reduction) with close monitoring. Consider therapy modification
CycloSPORINE (Systemic): May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Echothiophate Iodide: May increase the serum concentration of Succinylcholine. Management: For patients receiving echothiophate iodide eye drops, consider using a neuromuscular-blocking agents other than succinylcholine. If succinylcholine is used, consider a reduced dose, and monitor for enhanced/prolonged effects. Consider therapy modification
Esmolol: May enhance the neuromuscular-blocking effect of Succinylcholine. Monitor therapy
Estrogen Derivatives: May increase the serum concentration of Succinylcholine. Monitor therapy
Lincosamide Antibiotics: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Lithium: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Local Anesthetics: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Loop Diuretics: May diminish the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Loop Diuretics may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Magnesium Salts: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Metoclopramide: May enhance the neuromuscular-blocking effect of Succinylcholine. Monitor therapy
Minocycline (Systemic): May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Opioid Agonists: Succinylcholine may enhance the bradycardic effect of Opioid Agonists. Monitor therapy
Phenelzine: May enhance the neuromuscular-blocking effect of Succinylcholine. Management: Consider a lower initial succinylcholine dose in patients taking phenelzine, or those who have taken phenelzine within the previous 2 weeks. Monitor for increased succinylcholine effects (eg, prolonged apnea) in patients who recently received phenelzine. Consider therapy modification
Pholcodine: May enhance the adverse/toxic effect of Neuromuscular-Blocking Agents. Specifically, anaphylaxis has been reported. Monitor therapy
Polymyxin B: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Management: If possible, avoid concomitant use of neuromuscular-blocking agents and polymyxin B. If concomitant use cannot be avoided, monitor for deeper, prolonged neuromuscular-blocking effects (eg, respiratory paralysis) in patients receiving this combination. Consider therapy modification
Procainamide: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
QuiNIDine: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
QuiNINE: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Avoid combination
Sertraline: May increase the serum concentration of Succinylcholine. Monitor therapy
Tetracyclines: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Vancomycin: May enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
Frequency not defined.
Cardiovascular: Bradycardia (higher with second dose; more frequent in children), cardiac arrhythmia, hypertension, hypotension, malignant hyperthermia, tachycardia
Dermatologic: Skin rash
Endocrine & metabolic: Hyperkalemia
Neuromuscular & skeletal: Fasciculations, jaw tightness, myalgia (postoperative), rhabdomyolysis (with possible myoglobinuric acute renal failure)
Ophthalmic: Increased intraocular pressure
Respiratory: Apnea, respiratory depression (prolonged)
<1%, postmarketing, and/or case reports: Abnormal bone growth (myositis ossificans; prolonged use), myopathy (acute quadriplegic myopathy syndrome; prolonged use)
ALERT: U.S. Boxed WarningRisk of Cardiac Arrest from Hyperkalemic Rhabdomyolysis:
There have been rare reports of acute rhabdomyolysis with hyperkalemia followed by ventricular dysrhythmias, cardiac arrest, and death after the administration of succinylcholine to apparently healthy children who were subsequently found to have undiagnosed skeletal muscle myopathy, most frequently Duchenne muscular dystrophy.
This syndrome often presents as peaked T-waves and sudden cardiac arrest within minutes after the administration of the drug in healthy appearing children (usually, but not exclusively, males, and most frequently 8 years of age or younger). There have also been reports in adolescents.
Therefore, when a healthy appearing infant or child develops cardiac arrest soon after administration of succinylcholine not felt to be due to inadequate ventilation, oxygenation, or anesthetic overdose, immediate treatment for hyperkalemia should be instituted. This should include administration of intravenous calcium, bicarbonate, and glucose with insulin, with hyperventilation. Due to the abrupt onset of this syndrome, routine resuscitative measures are likely to be unsuccessful. However, extraordinary and prolonged resuscitative efforts have resulted in successful resuscitation in some reported cases. In addition, in the presence of signs of malignant hyperthermia, appropriate treatment should be instituted concurrently.
Since there may be no signs or symptoms to alert the practitioner to which patients are at risk, it is recommended that the use of succinylcholine in children should be reserved for emergency intubation or instances where immediate securing of the airway is necessary, such as laryngospasm, difficult airway, full stomach, or for intramuscular use when a suitable vein is inaccessible.
Concerns related to adverse effects:
• Anaphylaxis: Severe anaphylactic reactions (some life-threatening and fatal) have been reported; immediate treatment (including epinephrine 1 mg/mL) for anaphylactoid and/or hypersensitivity reactions should be available during use. Use caution in patients with previous anaphylactic reactions to other neuromuscular blocking agents.
• Bradycardia: Risk of bradycardia may be increased with second dose and may occur more in children. Occurrence may be reduced by pretreating with anticholinergic agents (eg, atropine).
• Increased intraocular pressure (IOP): May increase IOP; avoid use in patients in which an increase in IOP is undesirable (eg, narrow-angle glaucoma, penetrating eye injuries).
• Intracranial pressure: May cause a transient increase in intracranial pressure (adequate anesthetic induction prior to administration of succinylcholine will minimize this effect).
• Intragastric pressure: May increase intragastric pressure, which could result in regurgitation and possible aspiration of stomach contents.
• Malignant hyperthermia: Use may be associated with acute onset of malignant hyperthermia; risk may be increased with concomitant administration of volatile anesthetics.
• Neuromuscular cross-sensitivity: Cross-sensitivity with other neuromuscular-blocking agents may occur; use extreme caution in patients with previous anaphylactic reactions to other neuromuscular-blocking agents.
• Vagal tone: May increase vagal tone.
• Burn injury: Use with caution in patients with extensive or severe burns; risk of hyperkalemia is increased following injury. Onset of time and duration of risk are variable, but risk is generally greatest 7 to 10 days after injury. Resistance may occur in burn patients (≥20% of total body surface area), usually several days after the injury, and may persist for several months after wound healing (Han 2009).
• Conditions that may antagonize neuromuscular blockade (decreased paralysis): Respiratory alkalosis, hypercalcemia, demyelinating lesions, peripheral neuropathies, denervation, muscle trauma, and diabetes mellitus may result in antagonism of neuromuscular blockade (ACCM/SCCM/ASHP [Murray 2002]; Greenberg 2013; Miller 2010; Naguib 2002).
• Conditions that may potentiate neuromuscular blockade (increased paralysis): Electrolyte abnormalities (eg, severe hypocalcemia, severe hypokalemia, hypermagnesemia), neuromuscular diseases, metabolic acidosis, respiratory acidosis, Eaton-Lambert syndrome, and myasthenia gravis may result in potentiation of neuromuscular blockade (Greenberg 2013; Miller 2010; Naguib 2002).
• Fractures/muscle spasm: Use with caution in patients with fractures or muscle spasm; initial muscle fasciculations may cause additional trauma.
• Hyperkalemia: Use with extreme caution in patients with pre-existing hyperkalemia. Severe hyperkalemia may develop in patients with chronic abdominal infections, burn injuries, multiple trauma/crush injuries, extensive denervation of skeletal muscle, upper motor neuron injury, subarachnoid hemorrhage, or conditions which cause degeneration of the central and peripheral nervous system.
• Plasma pseudocholinesterase disorders: Metabolized by plasma cholinesterase; use with caution (if at all) in patients suspected of being homozygous for the atypical plasma cholinesterase gene. Plasma cholinesterase activity may also be reduced by burns, anemia, decompensated heart disease, infections, malignant tumors, myxedema, pregnancy, severe hepatic or renal dysfunction, peptic ulcer, and certain medications and chemicals.
• Elderly: Use with caution in the elderly, effects and duration are more variable.
• Pediatric: [US Boxed Warning]: Use caution in children and adolescents. Acute rhabdomyolysis with hyperkalemia, ventricular arrhythmias and cardiac arrest have been reported (rarely) in children with undiagnosed skeletal muscle myopathy (eg, Duchenne muscular dystrophy); occurs soon after administration and requires immediate treatment of hyperkalemia. Prolonged resuscitation may be required. Use in children should be reserved for emergency intubation when immediate airway control is necessary (eg, laryngospasm, difficult airway, full stomach), or IM use when a suitable vein is inaccessible.
• Appropriate use: Maintenance of an adequate airway and respiratory support is critical. All patients should receive eye care including liberal use of lubricating drops, gel, or ointment and eyelids should remain closed during continuous neuromuscular blockade to protect against damage to the cornea (ulceration and dryness).
• Experienced personnel: Should be administered by adequately trained individuals familiar with its use.
• Risk of medication errors: Accidental administration may be fatal. Confirm proper selection of intended product, store vial so the cap and ferrule are intact and the possibility of selecting the wrong product is minimized, and ensure that the intended dose is clearly labeled and communicated, when applicable.
Vital signs (heart rate, blood pressure, respiratory rate); degree of muscle paralysis (eg, presence of spontaneous movement, ventilator asynchrony, shivering, and consider use of a peripheral nerve stimulator with train of four monitoring along with clinical assessments); serum potassium and calcium
In the ICU setting, prolonged paralysis and generalized myopathy, following discontinuation of agent, may be minimized by appropriately monitoring degree of blockade.
Sensitivity to succinylcholine may be increased due to a decrease in plasma cholinesterase activity in patients taking chronic oral contraceptives.
Small amounts cross the placenta. Sensitivity to succinylcholine may be increased due to a ~24% decrease in plasma cholinesterase activity during pregnancy and several days postpartum; prolonged maternal apnea may be observed. Newborns of mothers with atypical plasma cholinesterase or those exposed to repeated or high doses of succinylcholine during cesarean delivery should be monitored for apnea and flaccidity.
What is this drug used for?
• It is used to calm muscles during surgery.
• It is used to calm muscles while on a breathing machine.
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
• Slow heartbeat
• Severe dizziness
• Passing out
• Severe headache
• Vision changes
• Muscle pain
• Muscle weakness
• Dark urine
• Unable to pass urine
• Eye pain
• Chest pain
• High potassium like abnormal heartbeat, confusion, dizziness, passing out, weakness, shortness of breath, or numbness or tingling feeling.
• Malignant hyperthermia like fast heartbeat, fast breathing, fever, spasm of jaw muscles, or stiffness of jaw muscles.
• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.
Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
More about succinylcholine
- Side Effects
- During Pregnancy
- Dosage Information
- Drug Interactions
- 35 Reviews
- Drug class: neuromuscular blocking agents
- FDA Alerts (4)