What is the best muscle relaxer for pediatric patients?

Best Muscle Relaxer for Pediatric Patients

For rapid-sequence induction in pediatric anesthesia, succinylcholine is the first-line muscle relaxant with age-specific dosing (<1 month: 1.8 mg/kg; >1 month to <1 year: 2.0 mg/kg; >1 year to <10 years: 1.2 mg/kg; >10 years: 1.0 mg/kg), while rocuronium >0.9 mg/kg serves as the alternative when succinylcholine is contraindicated. 1

Context-Specific Recommendations

For Anesthetic Procedures

Rapid-Sequence Induction:

• Succinylcholine remains the expert choice for rapid-sequence induction in children, providing the fastest onset and most reliable intubation conditions 1
• The time between loss of consciousness and airway protection must be minimized because apnea duration without hypoxemia is significantly shorter in younger children 1
• In children under 3 years of age, co-administer atropine 0.02 mg/kg to prevent bradycardia or cardiac arrest 1

When Succinylcholine is Contraindicated:

• Rocuronium at doses >0.9 mg/kg provides an acceptable alternative 1
• Note that as of 2018, sugammadex (the reversal agent for rocuronium) had not received marketing approval for children, limiting reversal options 1, 2

Conventional Induction:

• Muscle relaxants improve intubation conditions during intravenous induction compared to hypnotic/opioid combinations alone 1
• During inhaled induction in infants, muscle relaxants provide documented benefits for intubation conditions and reduce respiratory events 1, 3

Laryngospasm Management:

• Succinylcholine 1.0 mg/kg IV (or 4.0 mg/kg IM/sublingual) is most effective for complete laryngospasm 1
• Low-dose rocuronium or atracurium (0.1-0.2 mg/kg) may suffice for incomplete glottic closure if anesthetic depth is adequate 1
• Immediate availability of succinylcholine and atropine in pediatric operating theaters reduces cardiac arrest and severe airway obstruction by nearly 50% 1

For Spasticity Management

Baclofen is the most effective muscle relaxant for treating spasticity in pediatric patients with cerebral palsy or brain injury:

• Intrathecal baclofen represents the most effective treatment for diffuse spasticity of cerebral or spinal origin in pediatric patients 4, 5
• Oral baclofen is prescribed at 0.3-1.0 mg/kg/dose for pediatric patients 6
• Critical FDA warning: Safety and effectiveness in pediatric patients below age 12 years have not been established for oral baclofen 7
• Despite FDA labeling, clinical experience demonstrates benefits in younger children with severe spasticity, particularly via intrathecal administration 5

Critical Contraindications

Never use succinylcholine in:

• Primary muscle disorders (myopathies) - causes generalized contraction with rhabdomyolysis 1
• Conditions with up-regulation of nicotinic acetylcholine receptors (chronic motor deficits, extensive burns, prolonged critical illness) - causes life-threatening hyperkalemia 1, 8

For patients with myasthenia:

• Non-depolarizing muscle relaxants show increased sensitivity and prolonged duration 1
• Reduce atracurium and cisatracurium doses by 50-75% 1

Mandatory Monitoring

Neuromuscular blockade monitoring is essential in pediatric anesthesia:

• Residual neuromuscular blockade occurs in 28% of children receiving muscle relaxants 1, 2
• Monitor to train-of-four ratio ≥0.9 before extubation 1
• For patients with neuromuscular disease, monitoring prevents overdosing and guides dose adjustments 1

Key Clinical Pitfalls

• The allergic risk with muscle relaxants in pediatric populations is low but incompletely characterized 1, 3
• High doses of hypnotics/opioids used to avoid muscle relaxants cause significant hemodynamic effects 1
• Depolarizing muscle relaxants should not be used for routine intravenous induction outside rapid-sequence scenarios 1
• Baclofen withdrawal can cause seizures and life-threatening symptoms in pediatric patients 9