What are safe muscle relaxers for pediatric patients?

Safe Muscle Relaxants for Pediatric Patients

For pediatric patients requiring muscle relaxation, rocuronium is the safest first-line non-depolarizing muscle relaxant for anesthetic procedures, while methocarbamol is recommended for musculoskeletal conditions. 1

Muscle Relaxants for Anesthetic Procedures

Rapid Sequence Induction

• Succinylcholine remains the expert choice for rapid sequence induction in children when not contraindicated, with age-appropriate dosing: <1 month: 1.8 mg/kg, 1 month to 1 year: 2.0 mg/kg, 1-10 years: 1.2 mg/kg, >10 years: 1.0 mg/kg 2
• Rocuronium (>0.9 mg/kg) is the recommended alternative when succinylcholine is contraindicated 2
• In rapid sequence induction, use of a rapid-onset muscle relaxant is strongly recommended in children (Grade 1+) 2

Contraindications and Special Considerations

• Succinylcholine is contraindicated in cases of:
  • Primary muscle damage (myopathies) 2
  • Up-regulation of nicotinic acetylcholine receptors at the motor end plate (chronic motor deficit) 2
  • Neuromuscular diseases due to risk of rhabdomyolysis or life-threatening hyperkalemia 1
• Monitoring of neuromuscular blockade is essential, as residual neuromuscular blockade occurs in approximately 28% of children receiving muscle relaxants 2, 1

Other Anesthetic Muscle Relaxants

• Atracurium (0.1-0.2 mg/kg) is recommended for airway obstruction related to supraglottic devices when depth of anesthesia is adequate 3
• Atracurium is particularly useful in patients with renal or hepatic failure due to its organ-independent elimination 3
• Non-depolarizing muscle relaxants like mivacurium are also acceptable alternatives for pediatric anesthetic procedures 1, 4

Muscle Relaxants for Musculoskeletal Conditions

First-Line Agents

• Methocarbamol is commonly prescribed and recommended for acute muscle spasms in pediatric patients 1
• Cyclobenzaprine has been evaluated in the most clinical trials and consistently found effective for musculoskeletal conditions 5

Other Options

• Carisoprodol, chlorzoxazone, and metaxalone are also recommended for musculoskeletal conditions in adolescents 1
• These agents should be used for acute musculoskeletal pain rather than chronic conditions due to limited evidence for efficacy in chronic pain 1

Clinical Considerations

Monitoring

• Intraoperative monitoring of neuromuscular blockade is strongly recommended when using muscle relaxants 3
• The corrugator supercilii muscle is the preferred site for monitoring due to its sensitivity to muscle relaxants and kinetics comparable to laryngeal muscles 3

Dosing Adjustments

• Children generally require higher doses of non-depolarizing muscle relaxants on a mg/kg basis than infants or adults 4
• Children recover from neuromuscular blockade more rapidly than other age groups 4
• No dose modification is required for atracurium in patients with renal or hepatic failure 3

Safety Considerations

• Recent developments in clinical practice have reduced the need for muscle relaxants in pediatric anesthesia, but they remain indicated for intubation and procedures requiring profound muscle relaxation 6
• The choice of skeletal muscle relaxant for musculoskeletal conditions should be based on its adverse-effect profile, tolerability, and cost, as efficacy data does not strongly favor one agent over another 7
• Dantrolene and chlorzoxazone have been associated with rare serious hepatotoxicity and should be used with caution 5