When to avoid using succinylcholine (SCh), a depolarizing neuromuscular blocking agent?

From the Guidelines

Succinylcholine should be avoided in patients with Duchenne muscular dystrophy (DMD), significant hyperkalemia, recent major burns, crush injuries, denervation injuries, or neuromuscular diseases due to its potential for serious adverse effects, including rhabdomyolysis, hyperkalemia, and cardiac arrest 1. When considering the use of succinylcholine, it is crucial to weigh the potential benefits against the risks of severe complications. The evidence suggests that succinylcholine can trigger life-threatening conditions, such as malignant hyperthermia, in susceptible patients 1. Additionally, patients with significant hyperkalemia (potassium levels >5.5 mEq/L) should not receive succinylcholine, as it can cause further potassium release and potentially fatal cardiac arrhythmias 1.

Key Contraindications for Succinylcholine

• Malignant hyperthermia susceptibility
• Significant hyperkalemia (potassium levels >5.5 mEq/L)
• Recent major burns
• Crush injuries
• Denervation injuries
• Neuromuscular diseases (like muscular dystrophy)
• Personal or family history of pseudocholinesterase deficiency

Safer Alternatives

In situations where succinylcholine is contraindicated, rocuronium (0.9-1.2 mg/kg) is often a safer alternative 1. This is particularly important in pediatric patients, especially males under 8 years old, where the risk of undiagnosed muscular dystrophy leading to rhabdomyolysis and hyperkalemic cardiac arrest is a concern 1.

Clinical Considerations

It is essential to carefully evaluate each patient's medical history and current condition before administering succinylcholine. In patients with DMD, the use of depolarizing muscle relaxants like succinylcholine is absolutely contraindicated due to the risk of fatal reactions 1. By prioritizing patient safety and considering the potential risks and benefits, healthcare providers can make informed decisions about the use of succinylcholine in various clinical scenarios.

From the FDA Drug Label

Succinylcholine should be used only by those skilled in the management of artificial respiration and only when facilities are instantly available for tracheal intubation and for providing adequate ventilation of the patient, including the administration of oxygen under positive pressure and the elimination of carbon dioxide. Succinylcholine is metabolized by plasma cholinesterase and should be used with caution, if at all, in patients known to be or suspected of being homozygous for the atypical plasma cholinesterase gene. Anaphylaxis Severe anaphylactic reactions to neuromuscular blocking agents, including succinylcholine, have been reported. GREAT CAUTION should be observed if succinylcholine is administered to patients during the acute phase of injury following major burns, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury. Patients with chronic abdominal infection, subarachnoid hemorrhage, or conditions causing degeneration of central and peripheral nervous systems should receive succinylcholine with GREAT CAUTION because of the potential for developing severe hyperkalemia Malignant Hyperthermia Succinylcholine administration has been associated with acute onset of malignant hyperthermia, a potentially fatal hypermetabolic state of skeletal muscle.

Key situations to avoid using succinylcholine (SCh) include:

• Patients with known or suspected homozygous atypical plasma cholinesterase gene
• Patients with history of anaphylactic reactions to neuromuscular blocking agents
• Patients with electrolyte abnormalities or massive digitalis toxicity
• Patients during the acute phase of injury following major burns, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury
• Patients with chronic abdominal infection, subarachnoid hemorrhage, or conditions causing degeneration of central and peripheral nervous systems
• Patients at risk of malignant hyperthermia, especially with concomitant administration of volatile anesthetics 2 2

From the Research

Conditions to Avoid Succinylcholine

• Hyperkalemia: Patients with serum potassium levels >5.5 mEq/L should be cautious when using succinylcholine, as it can lead to further increases in potassium levels 3, 4, 5.
• Trauma: Patients with recent trauma, especially those with tissue wasting, infection, immobility, or acute respiratory acidosis, may be at risk for hyperkalemia when administered succinylcholine 4.
• Neuromuscular disease: Patients with neuromuscular diseases, such as Duchene muscular dystrophy, may be susceptible to malignant hyperthermia when given succinylcholine 6, 7.
• Bedridden patients: Prolonged bed rest can lead to receptor dysregulation, increasing the risk of hyperkalemia when succinylcholine is administered 6.
• Rhabdomyolysis: Patients with rhabdomyolysis may be at risk for hyperkalemia when given succinylcholine 6.
• Burns: Patients with burns may be at risk for hyperkalemia when administered succinylcholine 6.
• Infusion of neuromuscular blocking agents: Concomitant use of other neuromuscular blocking agents may increase the risk of hyperkalemia when succinylcholine is given 6.
• Acute or chronic renal failure: Patients with renal failure may be at risk for hyperkalemia when administered succinylcholine 6.
• Intraocular or intracranial hypertension: Patients with increased pressure in the eyes or brain may be at risk for further complications when given succinylcholine 6.
• Statin use: Concomitant use of statins may increase the risk of hyperkalemia when succinylcholine is administered 6.
• Malignant hyperthermia susceptibility: Patients with a history of malignant hyperthermia or susceptibility to it should avoid succinylcholine, as it can trigger the condition 7.
• Bradycardia: Patients with heart rates < 50 bpm may be at risk for further cardiac complications when administered succinylcholine 6.
• Succinylcholine allergy or pseudo-cholinesterase deficiency: Patients with a known allergy to succinylcholine or pseudo-cholinesterase deficiency should avoid its use 6.