What is the recommended treatment dosage for pediatric patients with Lyme disease?

Pediatric Lyme Disease Treatment Dosing

For pediatric patients with Lyme disease, amoxicillin at 50 mg/kg/day in 3 divided doses (maximum 500 mg per dose) is the recommended first-line treatment for children under 8 years of age, while doxycycline at 4 mg/kg/day in 2 divided doses (maximum 100 mg per dose) is recommended for children 8 years and older. 1

Treatment by Age Group

Children Under 8 Years

• First-line treatment: Amoxicillin 50 mg/kg/day divided into 3 doses (maximum 500 mg per dose) for 14-21 days 2, 1
• Alternative: Cefuroxime axetil 30 mg/kg/day in 2 divided doses (maximum 500 mg per dose) for 14-21 days 2
• Recent evidence: A twice-daily amoxicillin regimen of 25 mg/kg/dose (q12h) may provide comparable efficacy to the traditional three-times-daily regimen for improved adherence 3

Children 8 Years and Older

• First-line treatment: Doxycycline 4-8 mg/kg/day in 2 divided doses (maximum 100-200 mg per dose) for 10-14 days 2, 1
• Alternative options: Same as for younger children if doxycycline is contraindicated

Treatment by Clinical Presentation

Early Localized Disease (Erythema Migrans)

• Use oral antibiotics as outlined above for 14 days (range 10-21 days) 2, 1

Neurologic Involvement

• Without meningitis (isolated facial nerve palsy with normal CSF): Oral antibiotics as above for 14-21 days 2, 1
• With meningitis or other CNS involvement:
  • Ceftriaxone 50-75 mg/kg/day IV once daily (maximum 2g) for 14 days (range 10-28 days) 2
  • Alternatives: Cefotaxime 150-200 mg/kg/day IV divided into 3-4 doses (maximum 6g/day) or Penicillin G 200,000-400,000 units/kg/day IV divided every 4 hours (maximum 18-24 million units/day) 2

Lyme Carditis

• For mild cases: Oral antibiotics as above for 14-21 days
• For severe cases (advanced heart block or symptomatic): Initial IV antibiotics as per neurologic involvement, then transition to oral therapy to complete 14-21 days total 2

Important Clinical Considerations

• Doxycycline advantages: Covers potential co-infections with Human Granulocytic Anaplasmosis (HGA) 2, 1
• Treatment duration: Minimum 10 days for doxycycline and 14 days for amoxicillin 1
• Contraindications: Avoid doxycycline in children under 8 years due to potential dental staining, although recent evidence suggests short courses may be safe 4
• Ineffective treatments: First-generation cephalosporins (e.g., cephalexin) and macrolides should be avoided as first-line therapy due to lower efficacy 1

Monitoring and Follow-up

• Assess for clinical improvement within 48-72 hours of starting treatment
• Complete the full course of antibiotics even if symptoms resolve quickly
• For persistent symptoms after appropriate treatment, evaluate for other causes rather than extending antibiotic duration 1

Emerging Evidence

Recent studies suggest that doxycycline may be well-tolerated in children under 8 years with minimal risk of dental staining 4, and that oral doxycycline may be as effective as IV ceftriaxone for Lyme neuroborreliosis in pediatric patients 5. However, until these findings are incorporated into guidelines, the standard age-based recommendations should be followed.