Succinylcholine (Suxamethonium) is a short-acting depolarizing muscle relaxant that is used during rapid sequence endotracheal intubation.

Succinylcholine (Suxamethonium) Uses:

• Neuromuscular blockade for endotracheal intubation, surgery, or mechanical ventilation:

  • As an adjunct to general anesthesia to facilitate and potentiate tracheal intubation and to provide skeletal muscle relaxation during the surgical procedure or mechanical ventilation in adequately sedated patients

Note:

• The neuromuscular blockade does not provide pain relief, sedation, or amnestic effects.
• Appropriate analgesic and sedative mediations should be used before and during the administration of neuromuscular blockade to achieve deep sedation.

• Off Label Use of Succinylcholine in Adult

  • As a muscle relaxant in Electroconvulsive therapy.

Succinylcholine (Suxamethonium) Dose in Adults

Note:

• Doses may vary due to interpatient variability.
• Ensure adequate pain control and sedation before and during the administration of neuromuscular blockade.
• Use carefully and/or consider a reduction in dose in patients with reduced plasma cholinesterase activity due to genetic anomalies of plasma cholinesterase or when associated with other conditions (eg, electrolyte abnormalities, neuromuscular disease);
• prolonged neuromuscular blockade may occur.

Succinylcholine Dose as a muscle relaxant in the treatment of Electroconvulsive therapy (ECT):

• IV:

  • 0.5 to 1.5 mg/kg (doses ≥0.75 mg/kg are more commonly used in clinical practice)
  • adjust the dose higher or lower based on muscle mass, muscle relaxation with previous ECT, and patient-specific risks linked with suboptimal relaxation (eg, increase the dose in patients with osteoporosis).

Note:

• Most patients will recover respiratory function and muscle power/ strength within 9 to 10 minutes.

Succinylcholine Dose in the treatment of Neuromuscular blockade for endotracheal intubation, surgery, or mechanical ventilation (as an adjunct to general anesthesia):

• IM:

  • Up to 3 to 4 mg/kg,
  • A maximum total dose of 150 mg

• IV:

  • Intubation:
    • 0.6 mg/kg (range: 0.3 to 1.1 mg/kg)
  • Intubation (rapid sequence) (off-label dosing):
    • at 1 to 1.5 mg/kg (Sluga 2005; Weiss 1997)
  • Long surgical procedures (intermittent administration):
    • Initial: at 0.3 to 1.1 mg/kg;
    • administer at 0.04 to 0.07 mg/kg at appropriate intervals as needed.

Note:

• Pretreatment with atropine may reduce the occurrence of bradycardia.
• The initial dose of succinylcholine must be increased when nondepolarizing agent pretreatment is used because of the opposite effect between succinylcholine and nondepolarizing neuromuscular-blocking agents.
• When the cumulative dose of succinylcholine exceeds 2 to 4 mg/kg under general anesthesia or succinylcholine is administered in continuous infusion form, the transition from a phase I to a phase II block may occur.
• If the phase II block is suspected, the diagnosis must be confirmed by peripheral nerve stimulation before the administration of an anticholinesterase drug.

Succinylcholine (Suxamethonium) Dose in Children

Note:

• Dose to effect; doses vary due to interpatient variability.
• Use carefully and/or consider dose reduction in patients having reduced plasma cholinesterase activity due to genetic anomalies of plasma cholinesterase or when associated with some other conditions (eg, electrolyte abnormalities, neuromuscular disease); prolonged neuromuscular blockade may occur.
• The initial dose of succinylcholine must be increased when nondepolarizing agent pretreatment used because of the opposite effects between succinylcholine and nondepolarizing neuromuscular-blocking agents.
• Because of the risk of developing adverse effects including malignant hyperthermia and cardiac arrhythmias, in such cases surgical or long-term paralytic use (ie, continuous IV infusion) is not recommended.

Succinylcholine Dose in rapid sequence (emergent) endotracheal intubation:

Note:

• To reduce the risk of bradycardia or asystole, premedication with atropine is suggested before IV succinylcholine doses.

Infants, Children, and Adolescents:

• Note: In obese and overweight patients, pediatric patient data (age range: 9 to 15 years) recommend dosing based on using total body weight.

IM:

• Infants <6 months:

  • 4 to 5 mg/kg; pharmacokinetic data suggest that young infants typically require doses on the higher end of this range.

• Infants ≥6 months and Children:

  • 4 mg/kg;
  • maximum dose: 150 mg/dose.

• Adolescents:

  • 3 to 4 mg/kg;
  • maximum dose: 150 mg/dose

IV:

• Manufacturer's labeling:

  • Infants ≤6 months:

    • 2 to 3 mg/kg/dose

  • Infants >6 months and Children ≤2 years:

    • at 1 to 2 mg/kg/dose

  • Children >2 years and Adolescents:

    • 1 mg/kg/dose

• Alternate dosing: Limited data available:

  • Infants:

    • at 2 to 3 mg/kg/dose.

  • Children:

    • at 1 to 2 mg/kg/dose.

  • Adolescents:

    • at 1 to 1.5 mg/kg/dose.

Pregnancy Risk Category: C

• Studies on animal reproduction have not been done.
• The placenta can be crossed in small amounts.
• Due to the 24% drop in plasma cholinesterase activity during pregnancy and several days after birth, succinylcholine hyperresponsiveness/sensitivity may increase.

Use of succinylcholine during breastfeeding

• It is unknown if succinylcholine can be found in breast milk.
• Manufacturer recommends caution when giving succinylcholine for breastfeeding women.

Succinylcholine Dose in Kidney Disease:

• There are no dosage adjustments provided in the drug manufacturer's labeling.

Succinylcholine Dose in Liver disease:

• There are no dosage adjustments provided in the drug manufacturer's labeling.

Side effects of Succinylcholine:

• Cardiovascular:

  • Bradycardia (Higher with Second Dose; More Frequent In Children)
  • Cardiac Arrhythmia
  • Hypertension
  • Hypotension
  • Malignant Hyperthermia
  • Tachycardia

• Dermatologic:

  • Skin Rash

• Endocrine & Metabolic:

  • Hyperkalemia

• Gastrointestinal:

  • Sialorrhea

• Hypersensitivity:

  • Anaphylaxis

• Neuromuscular & Skeletal:

  • Fasciculations
  • Jaw Tightness
  • Myalgia (Postoperative)
  • Rhabdomyolysis (With Possible Myoglobinuric Acute Renal Failure)

• Ophthalmic:

  • Increased Intraocular Pressure

• Respiratory:

  • Apnea
  • Respiratory Depression (Prolonged)

Contraindications to Succinylcholine:

• Hypersensitivity/hyperresponsiveness of succinylcholine and any other component of the formulation
• Personal or familial history with malignant hyperthermia
• Myopathies of the skeletal muscles
• Use after major burns, multiple trauma, extensive denervation or injury to the upper motor neuron.
• There is not much evidence of allergenic cross-reactivity with neuromuscular blocking drugs.
• Cross-sensitivity can be possible due to similar chemical structures and/or pharmacologic activities.

Warnings and precautions

• Anaphylaxis

  • There have been severe anaphylactic reactions that can be fatal or life-threatening.
  • For hypersensitivity and anaphylactic reactions, immediate treatment should be provided (epinephrine 1mg/mL).
  • Patients with a history of anaphylactic reactions to neuromuscular blocking agents should be cautious.

• Bradycardia

  • Bradycardia can occur in children more often than adults and may increase with each additional dose. Pretreatment with anticholinergic drugs (eg atropine) may reduce the risk of bradycardia.

• An increase in intraocular pressure (IOP).

  • May raise IOP
  • Avoid use in patients with high IOP (e.g., narrow-angle or penetrating eyes injuries, or narrow-angle glaucoma).

• Intracranial pressure

  • This may cause an intracranial rise in pressure. Adequate anesthetic injection before succinylcholine administration will reduce this effect.

• Intragastric pressure

  • May increase intragastric pressure which could lead to regurgitation or aspiration.

• Malignant hyperthermia

  • Consumption may cause malignant hyperthermia, which can be severe.

• Cross-sensitivity of neuromuscular neurons:

  • It is possible to cross-sensitive with other neuromuscular-blocking drugs.
  • Patients who have had anaphylactic reactions to any of the neuromuscular-blocking agent should be treated with extreme caution.

• Vagal tone

  • May increase vagal tone

• Burn injury

  • Patients with severe or extensive burns should be cautious.
  • Injury increases the risk of hyperkalemia.
  • Variable factors can affect the time of injury and the duration of the risk. However, it is common for injuries to occur between 7-10 days after an injury.
  • Patients with burn injuries may experience resistance (>=20% total body surface area). This can occur within days or weeks of the injury and may continue for many months.

• Conditions that could lead to neuromuscular blockade (decreased parity)

  • Antagonism of neuromuscular blockade may be caused by hypercalcemia, respiratory alkalosis and demyelinating lesion, peripheral neuropathies and denervation, diabetes mellitus, demyelinating lesions, dermal hypercalcemia, desyelinating disorders, peripheral neuropathies, neuropathies, neuropathies, muscle trauma, or other conditions such as respiratory alkalosis, hypercalcemia and demyelinating diseases, diabetic mell

• Conditions that can cause neuromuscular blockade (increased parity):

  • Electrolyte abnormalities, eg severe hypocalcemia or severe hypokalemia, hypermagnesemia
  • Neuromuscular diseases
  • Metabolic acidosis
  • Respiratory acidosis
  • Eaton-Lambert syndrome
  • Myasthenia gravis and may lead to neuromuscular blockade.

• Fractures/muscle spasm

  • Patients with muscle spasm or fractures should be cautious
  • Additional trauma may result from initial muscle fasciculations.

• Hyperkalemia

  • Patients with hyperkalemia are advised to exercise extreme caution.
  • Patients with chronic abdominal infections, burns, multiple trauma/crush injury, severe hyperkalemia, and extensive denervation may develop.

• Plasma pseudocholinesterase diseases:

  • Patients who have a suspicion of having the same genetic trait as the atypical plasma cholesterol gene should be cautious.
  • Anemia, decompensated cardiac disease, burns, myxedema and certain medications can also reduce plasma cholinesterase activity.

Succinylcholine (suxamethonium): Drug Interaction

Monitoring parameters:

• Vital signs (heart rate and blood pressure, respiratory rate)
• The severity of muscle paralysis (i.e., presence of spontaneous movements, ventilator asynchrony and shivering or chills) and the use of a peripheral neuro stimulator with a train four monitoring in addition to clinical assessments;
• Serum potassium and serum calcium
• If the level of blockade is properly monitored in the ICU, prolonged paralysis and generalized myopathy may be reduced.

How to administer Succinylcholine or Suxamethonium?

• IM: Administer deep IM only in cases when IV access is not available.
• IV: May be administered concentrated by rapid IV injection.

Mechanism of action of Succinylcholine or Suxamethonium:

• The same act as acetylcholine causes motor endplate depolarization at the myoneural junction, which then causes flaccid skeletal muscles paralysis.
• This is caused by accommodation in adjacent excitable membranes.

The onset of action:

• Dependent on the route, age, and dose; data suggest a faster onset with larger doses:
• IM:
  • Infants and Children: in 3 to 4 minutes.
  • Adults: 2 to 3 minutes
• IV:
  • Neonates and Infants: approximately 30 seconds (range: 19 to 40 seconds [dose: 2 to 4 mg/kg])
  • Children and Adolescents: in 35 to 55 seconds.
    • Dose-specific: 40 seconds (dose: 1.5 to 2 mg/kg);
    • 50 seconds (dose: 1 mg/kg).
  • Adults: Flaccid paralysis: <60 seconds

Duration of action:

• Dependent on the 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.

Distribution:

• V higher in neonates and infants due to larger ECF volume; higher IV doses necessary

Metabolism:

• Rapidly hydrolyzed by plasma pseudocholinesterase to inactive metabolites

Excretion:

• Urine (~10% excreted unchanged)

International Brands of Suxamethonium:

• Anectine
• Quelicin
• Quelicin Chloride
• Anectine
• Anekcin
• Anektil
• Celocurin
• Celocurine
• Chlorsuccillin
• Curacit
• Distensil
• Ethicholine
• Fosfitone
• Leptosuccin
• Lysthenon
• Midarine
• Mioflex
• Myoplegine
• Myotenlis
• Neosuxa
• Pantolax
• Quelicin Chloride
• Relaxin
• Scoline
• Succi
• Succicholine
• Succinil
• Succinyl Asta
• Succinyl Forte
• Sukolin
• Sulax
• Sumeth
• Suxa
• Suxamethonium
• Suxameton
• Suxametonio cloruro
• Suxametonio Cloruro
• Uccmasuccin
• Vetorelaxia
• Zuxelax

Suxamethonium Brands Names in Pakistan: