What is the recommended dose of baclofen (GABA receptor agonist) for an 18-month-old child with neck spasticity due to viral encephalitis?

Baclofen Dosing for Neck Spasticity in an 18-Month-Old Child with Viral Encephalitis

For an 18-month-old child with neck spasticity due to viral encephalitis, oral baclofen should be initiated at 2.5 mg/day (0.2-0.3 mg/kg/day) divided into 3-4 doses, with gradual titration by 2.5 mg increments every 3 days as needed and tolerated, up to a maximum of 20-40 mg/day.

Initial Management of Viral Encephalitis

Before addressing spasticity management specifically, it's important to ensure appropriate treatment of the underlying viral encephalitis:

• Confirm diagnosis through neuroimaging (preferably MRI) and CSF analysis 1
• If HSV encephalitis is confirmed or suspected, administer IV acyclovir:
  • For children 3 months-12 years: 500 mg/m² IV every 8 hours for 21 days 1
  • Ensure adequate hydration to prevent acyclovir-induced nephropathy 1

Baclofen for Spasticity Management

Starting Dose and Titration

• Initial dose: 2.5 mg/day (approximately 0.2-0.3 mg/kg/day) divided into 3-4 doses
• Titration: Increase by 2.5 mg increments every 3 days
• Target: Effective dose with minimal side effects
• Maximum dose: 20-40 mg/day total, depending on response and tolerability

Administration Considerations

• Oral baclofen should be administered with meals to minimize gastrointestinal side effects
• Divided dosing (3-4 times daily) helps maintain consistent blood levels and reduces side effects
• Liquid formulation may be preferable for accurate dosing in this age group

Monitoring and Precautions

Side Effects to Monitor

• Sedation/somnolence (most common)
• Hypotonia/weakness
• Respiratory depression
• Seizures (rare)
• Gastrointestinal disturbances
• Behavioral changes

Important Precautions

• Never abruptly discontinue baclofen as withdrawal can cause seizures, psychosis, and hyperthermia 2
• If discontinuation is needed, taper slowly over 1-2 weeks
• Use with caution in patients with renal impairment 2
• Monitor for potential drug interactions, particularly with other CNS depressants

Alternative Approaches

If oral baclofen is ineffective or poorly tolerated:

1. Consider other oral antispasticity medications:

   • Tizanidine (may have better tolerability profile than baclofen) 2
   • Dantrolene (acts directly on muscle)

2. For severe, refractory spasticity:

   • Intrathecal baclofen may be considered in specialized centers, though this is rarely used as first-line therapy in young children 3, 4
   • Botulinum toxin injections for focal spasticity

Special Considerations for Young Children

• Baclofen neurotoxicity risk is higher in young children - monitor closely for signs of encephalopathy 5
• Avoid concurrent use of benzodiazepines which can exacerbate baclofen's sedative effects 5
• Regular reassessment is essential to evaluate efficacy and adjust dosing as the child grows

Treatment Success Evaluation

• Reduction in muscle tone/spasticity
• Improved range of motion
• Enhanced comfort and ease of care
• Better sleep quality
• Improved positioning and prevention of contractures

This approach balances the need to treat spasticity while minimizing the risk of adverse effects in this vulnerable pediatric population.