What is the recommended oral baclofen dose per kilogram for a child with cerebral palsy?

Oral Baclofen Dosing for Children with Cerebral Palsy

For children with cerebral palsy aged 2-17 years, initiate oral baclofen at 2.5 mg three times daily and titrate gradually to a target maintenance dose of approximately 2 mg/kg/day, divided into 3-4 doses, with a typical maximum of 20 mg four times daily (80 mg/day total). 1

Initial Dosing Strategy

• Start with 2.5 mg three times daily in children over 2 years of age 1
• This conservative starting dose minimizes CNS-related side effects while establishing tolerance 2
• The pharmacokinetic profile supports weight-based dosing from the outset, as baclofen exhibits dose-proportional and weight-proportional kinetics 1

Titration Protocol

• Increase gradually over 10-12 weeks to reach the target maintenance dose 1
• The population pharmacokinetic data demonstrates that 2 mg/kg/day is an appropriate target for most children with cerebral palsy 1
• Baclofen has a terminal half-life of approximately 4.5 hours in children, supporting 3-4 times daily dosing 1
• Maximum tolerated doses typically reach 20 mg four times daily (80 mg/day total), though some children may require higher doses 1

Weight-Based Dosing Rationale

• Body weight is a significant determinant of baclofen clearance in children with CP 1
• Apparent clearance averages 0.273 L/h/kg with moderate inter-individual variability (33.4%) 1
• Both R- and S-baclofen enantiomers show identical concentration-time profiles and linear pharmacokinetics 1
• Age also influences clearance, supporting the weight-based approach for children 2-17 years 1

Practical Dosing Examples

For a typical child:

• 10 kg child: Target ~20 mg/day (e.g., 5-7 mg three times daily)
• 20 kg child: Target ~40 mg/day (e.g., 10-15 mg three times daily)
• 30 kg child: Target ~60 mg/day (e.g., 15-20 mg three times daily or four times daily)

Higher Dose Requirements

• Mean dosages of 40 mg/day are commonly required, with maximum dosages reaching 240 mg/day in some children 3
• Duration post-injury, age, and concomitant antispasticity medications predict higher baclofen requirements 3
• The current dose escalation strategy (starting low and titrating gradually) is appropriate and supported by pharmacokinetic data 1

Clinical Response Monitoring

• Oral baclofen provides mild to moderate improvement in cerebral spasticity, though its efficacy is limited by poor lipid solubility 4
• If oral baclofen proves ineffective at maximum tolerated doses or causes excessive CNS side effects, intrathecal baclofen therapy should be considered 2, 4
• Intrathecal dosing ranges from 22-1400 μg/day, with most patients maintained on 90-703 μg/day 2

Common Pitfalls to Avoid

• Do not escalate too rapidly: The 10-12 week titration period allows assessment of therapeutic response while minimizing sedation and confusion 1
• Avoid underdosing: Many children require doses higher than initially anticipated, particularly those with longer duration post-injury 3
• Monitor for CNS effects: Drowsiness and confusion can occur, particularly in younger children, though these typically resolve quickly 5
• Consider intrathecal therapy early: If oral doses exceed 80-100 mg/day without adequate spasticity control, intrathecal baclofen may be more effective and better tolerated 2, 4

Limitations of Oral Therapy

• Single intrathecal doses of 25-100 μg significantly reduce lower extremity spasticity within 2 hours, demonstrating superior efficacy compared to oral administration 5
• Oral baclofen has minimal effect on upper extremity tone and function at typical doses 5
• For severe generalized spasticity affecting both upper and lower extremities, intrathecal baclofen is more effective 4