Ceftriaxone Pediatric Dosing
For most pediatric infections, ceftriaxone should be dosed at 50-75 mg/kg/day given once daily, with bacterial meningitis requiring 100 mg/kg/day (maximum 4 g daily), divided every 12-24 hours. 1
Age-Specific Dosing Considerations
Neonates
- Postnatal age ≤7 days: 50 mg/kg/day given every 24 hours 1
- Postnatal age >7 days and weight ≤2000 g: 50 mg/kg/day given every 24 hours 1
- Postnatal age >7 days and weight >2000 g: 50-75 mg/kg/day given every 24 hours 1
- Critical contraindication: Do not use ceftriaxone in hyperbilirubinemic neonates due to risk of bilirubin displacement 1
Infants and Children
The dosing varies significantly based on infection severity and pathogen:
Indication-Specific Dosing
Bacterial Meningitis (Highest Priority)
- 100 mg/kg/day divided every 12-24 hours (maximum 4 g daily) 1
- This higher dose is essential for adequate CSF penetration, which averages only 4.8% of plasma concentrations 2
- Recent pharmacokinetic modeling demonstrates that once-daily dosing (100 mg/kg) achieves superior CSF target attainment (88% PTA at 24h) compared to twice-daily dosing (50 mg/kg BD, 53% PTA) for pathogens with MIC ≤1 mg/L 3
Severe Infections (Pneumonia, Sepsis, Complicated Intra-abdominal Infections)
- 50-100 mg/kg/day given once daily or divided every 12-24 hours 1
- For pneumococcal pneumonia with penicillin resistance: 100 mg/kg/day every 12-24 hours 1, 4
Less Severe Infections
- 50-75 mg/kg/day given once daily or divided every 12-24 hours 1
Pathogen-Specific Considerations
Penicillin-Resistant Streptococcus pneumoniae
- MIC ≥4.0 μg/mL: 100 mg/kg/day every 12-24 hours 4
- MIC <2.0 μg/mL: 50-100 mg/kg/day every 12-24 hours 4
HACEK Organisms (Endocarditis)
- 100 mg/kg/day IV/IM once daily for 4 weeks (native valve) or 6 weeks (prosthetic valve) 5
Gram-Negative Enteric Bacilli
- 100 mg/kg/day divided every 12 hours or 80 mg/kg/day every 24 hours (maximum 4 g daily) 1
Group A Streptococcus and β-lactamase Producing Haemophilus influenzae
- 50-100 mg/kg/day every 12-24 hours 4
Critical Dosing Nuances
Once-Daily vs. Twice-Daily Debate
The evidence strongly supports once-daily dosing for most indications:
- Pharmacokinetic advantage: Ceftriaxone has a prolonged elimination half-life of 4.2-4.6 hours in pediatric patients 2, 6
- Clinical efficacy: Studies demonstrate 94-98% cure rates with once-daily dosing at 50-100 mg/kg 7, 8
- Exception for critically ill: In patients with estimated GFR >80 mL/min/1.73 m² or areas with less-susceptible pathogens (MIC ≥0.5 mg/L), consider 50 mg/kg twice daily to improve target attainment (93.4% vs 60.8% PTA) 9
Maximum Dose Limitations
Administration Considerations
- IV infusion should occur over 30 minutes 6
- IM injection is painful and patients should be counseled accordingly 5
Common Pitfalls to Avoid
- Underdosing meningitis: Using 50 mg/kg instead of 100 mg/kg for CNS infections results in inadequate CSF concentrations 3
- Using ceftriaxone in jaundiced neonates: Risk of kernicterus from bilirubin displacement 1
- Assuming twice-daily is always better: Once-daily dosing achieves superior early target attainment for meningitis 3
- Inadequate dosing for resistant organisms: Staphylococcus aureus meningitis (MIC 4 mg/L) requires alternative therapy as neither standard regimen achieves adequate CSF levels 3