Baclofen Dosing for Spasticity in Cerebral Palsy
For oral baclofen in pediatric patients with cerebral palsy, start at 2.5 mg three times daily and titrate gradually over 10-12 weeks to a target dose of approximately 2 mg/kg/day (mean 40 mg/day), with maximum doses up to 80 mg/day (or rarely up to 240 mg/day in refractory cases). 1, 2
Oral Baclofen Dosing Strategy
Initial Dosing and Titration
- Start with 2.5 mg three times daily in children aged 2-17 years with cerebral palsy 2
- Titrate gradually in weekly increments to minimize common side effects of dizziness, somnolence, and gastrointestinal symptoms 3
- Target dose is approximately 2 mg/kg/day, which translates to a mean effective dose of 40 mg/day in most pediatric patients 1, 2
- Maximum recommended dose is typically 20 mg four times daily (80 mg/day), though some patients may require up to 240 mg/day for adequate spasticity control 1
Factors Affecting Dosing
- Body weight is the primary determinant of baclofen clearance and should guide dosing decisions 2
- Age and duration post-injury are additional predictive variables for required dosage, with older children and those further from injury onset potentially requiring higher doses 1
- Concomitant antispasticity medications may influence the required baclofen dose 1
Pharmacokinetic Considerations
- Baclofen exhibits dose-proportional pharmacokinetics with a terminal half-life of approximately 4.5 hours in children 2
- Both R- and S-enantiomers show identical concentration-time profiles, eliminating concerns about differential enantiomer effects 2
- The current dose escalation strategy over 10-12 weeks is appropriate based on population pharmacokinetic modeling 2
Comparative Efficacy with Other Oral Agents
- Baclofen and diazepam show equivalent efficacy in reducing spasticity as measured by Modified Ashworth Scale, with both achieving significant improvements at 1 and 3 months (p=0.0001 within groups, no significant difference between groups) 4
- Drowsiness is the most common side effect with both baclofen and diazepam, occurring at similar rates 4
- Both medications significantly improve range of motion in addition to reducing spasticity scores 4
Intrathecal Baclofen for Refractory Cases
When to Consider Intrathecal Administration
- Reserve intrathecal baclofen for severe spasticity unresponsive to oral medications or when oral agents cause dose-limiting side effects 3
- Consider as early as 3-6 months after injury in patients refractory to other treatments 3
- Appropriate for two patient populations: older ambulatory children with inadequate leg strength, and patients with severe spasticity in both upper and lower extremities 5
Intrathecal Dosing Protocol
- Confirm responsiveness with test bolus injections before pump insertion, using doses of 12.5-50 mcg (most commonly 25 mcg effective) 6
- Continuous infusion dosages range from 27-800 mcg/day via programmable subcutaneous pump 5
- Intrathecal administration achieves cerebrospinal fluid levels many times higher than oral administration due to baclofen's poor lipid solubility 5
Outcomes and Complications
- Intrathecal baclofen significantly reduces muscle tone, diminishes pain, and facilitates ease of care in carefully selected children 6
- Catheter-related complications occur in approximately 20% of patients 5
- Infection requiring pump removal occurs in approximately 5% of cases 5
- Symptoms of lowered cerebrospinal fluid pressure are common during the test phase 6
Critical Safety Considerations
- Discontinuation requires slow tapering to avoid potential toxicity, delirium, and seizures 3
- Monitor for sedation and drowsiness, which are dose-dependent and can be minimized by starting low and titrating cautiously 3, 4
- Baclofen has no effect on athetosis at dosages used to treat spasticity, so do not use for dyskinetic cerebral palsy without spastic components 5
- Preliminary evidence suggests benefit for generalized dystonia associated with cerebral palsy, though this is not the primary indication 5