To whom can succinylcholine not be given?

Absolute Contraindications to Succinylcholine

Succinylcholine is absolutely contraindicated in patients with personal or familial history of malignant hyperthermia, skeletal muscle myopathies (including Duchenne muscular dystrophy), and in patients after the acute phase of injury following major burns, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury due to the risk of fatal hyperkalemia and cardiac arrest. 1

Malignant Hyperthermia Risk

• Personal or familial history of malignant hyperthermia represents an absolute contraindication, as succinylcholine is a known trigger agent that can precipitate this potentially fatal hypermetabolic crisis 1
• Dantrolene must be immediately available wherever succinylcholine is used routinely, as malignant hyperthermia can present as masseter spasm, generalized rigidity, tachycardia, and profound hyperpyrexia 2, 3
• Patients can develop malignant hyperthermia even after previous uneventful anesthetics, so negative family history does not rule out susceptibility 3

Conditions Causing Receptor Upregulation (High Risk of Fatal Hyperkalemia)

The following conditions cause upregulation of nicotinic acetylcholine receptors, leading to massive potassium efflux and potential cardiac arrest:

Burns and Trauma

• Major burns (after 24-48 hours post-injury): Risk peaks at 7-10 days after injury and persists for weeks to months 1, 4
• Multiple trauma with extensive tissue damage 1
• Crush injuries beyond the acute phase 4, 3

Neuromuscular and Neurologic Conditions

• Skeletal muscle myopathies including Duchenne muscular dystrophy, Becker dystrophy, and other primary muscle diseases 1, 4
• Spinal cord injuries and upper motor neuron lesions 1, 5
• Denervation syndromes and extensive denervation of skeletal muscle 1, 4
• Neuromuscular diseases causing chronic motor neuron damage 4
• Multiple sclerosis (case reports of life-threatening hyperkalemia) 6

Immobilization and Critical Illness

• Prolonged immobilization (>3 days) or bedridden patients 4, 3, 7
• Prolonged critical illness with extended ICU stays 4, 7

Critical timing consideration: The risk of hyperkalemia increases over time and usually peaks at 7-10 days after injury, with the precise onset and duration of the risk period being undetermined but potentially lasting weeks to months 1

Pediatric-Specific Contraindications

• Undiagnosed myopathy in children (particularly boys <9 years old): Cardiac arrest can occur within minutes of succinylcholine administration in apparently healthy children with occult skeletal muscle myopathies 1, 4
• The syndrome often presents as sudden cardiac arrest with peaked T-waves on ECG, and routine resuscitative measures are frequently unsuccessful 1
• Succinylcholine is no longer recommended for elective pediatric anesthesia due to this risk 8

Other Absolute Contraindications

• Known hypersensitivity or allergy to succinylcholine 1
• Homozygous atypical plasma cholinesterase deficiency (1 in 2500 patients): These patients are extremely sensitive and may experience prolonged apnea 1

Relative Contraindications Requiring Great Caution

The FDA label specifies "GREAT CAUTION" (not absolute contraindication) for:

• Electrolyte abnormalities and massive digitalis toxicity (risk of cardiac arrhythmias) 1
• Chronic abdominal infection 1
• Subarachnoid hemorrhage 1
• Conditions causing degeneration of central and peripheral nervous systems 1
• Reduced plasma cholinesterase activity from pregnancy, liver/kidney disease, malignant tumors, infections, or medications (oral contraceptives, glucocorticoids, MAO inhibitors, organophosphate exposure) 1
• Patients receiving pyridostigmine: The American Society of Anesthesiologists recommends abstaining from succinylcholine use in these patients due to synergistic effects and unpredictable prolonged blockade 9

Recommended Alternative: Rocuronium

• Rocuronium 0.9-1.2 mg/kg IV is the preferred alternative when succinylcholine is contraindicated, providing excellent intubating conditions within 60 seconds 3, 4
• The main disadvantage is longer duration of action (30-60 minutes vs. 4-6 minutes), but the safety benefit outweighs this in high-risk patients 4, 3
• Protocolized post-intubation analgosedation must be implemented immediately when rocuronium is used to prevent awareness during prolonged neuromuscular blockade 3
• Sugammadex should be rapidly available for reversal if needed 3

Critical Clinical Pitfalls to Avoid

• Do not give repeat doses of succinylcholine after failed intubation in rapid sequence induction scenarios, as this increases risk of laryngospasm and aspiration 2
• Do not assume modest hyperkalemia is safe: While one retrospective study of 38 patients with preoperative potassium ≥5.6 mEq/L showed no immediate complications 10, this does not apply to patients with receptor upregulation conditions where even normal baseline potassium can lead to fatal hyperkalemia
• Do not underdose rocuronium: Use at least 0.9 mg/kg, preferably 1.0-1.2 mg/kg for optimal intubating conditions 3
• Do not rely on family history alone: Patients can develop malignant hyperthermia despite negative family history and previous uneventful anesthetics 3