Ceftriaxone Dosing for 1-Year-Old, 8.4 kg Pediatric Patient (Q24H)
For a 1-year-old child weighing 8.4 kg requiring once-daily ceftriaxone, the dose is 50-75 mg/kg/day (420-630 mg daily) for most infections, or 100 mg/kg/day (840 mg daily) for meningitis, administered as a single daily dose. 1, 2
Infection-Specific Dosing Algorithm
For Non-Meningeal Infections
Standard infections (skin/soft tissue, pneumonia, UTI, bacteremia):
- Dose: 50-75 mg/kg/day = 420-630 mg once daily 1, 2
- Use the higher end (75 mg/kg = 630 mg) for severe infections including pneumonia 1
- Use the lower end (50 mg/kg = 420 mg) for less severe infections 1
- Maximum daily dose should not exceed 2 grams 2
Severe community-acquired pneumonia:
- Dose: 50-100 mg/kg/day = 420-840 mg once daily 1
- For pneumococcal pneumonia with penicillin resistance: 100 mg/kg/day (840 mg) 1
Complicated intra-abdominal infections or sepsis:
- Dose: 50-75 mg/kg/day = 420-630 mg once daily 1
For Meningitis
Bacterial meningitis:
- Initial dose: 100 mg/kg (840 mg) as loading dose 2
- Maintenance: 100 mg/kg/day (840 mg) once daily or divided every 12 hours 1, 2
- Maximum 4 grams daily 1, 2
- Duration: 7-14 days 2
Administration Guidelines
Route and timing:
- Intravenous administration over 60 minutes is mandatory in this age group to reduce risk of bilirubin encephalopathy 2
- Intramuscular injection is an alternative but should be injected deep into a large muscle mass and is painful 3
Critical safety consideration:
- Do not use calcium-containing diluents (Ringer's solution, Hartmann's solution) as particulate formation can result 3, 2
Practical Dosing Examples for 8.4 kg Patient
| Indication | Dose (mg/kg/day) | Total Daily Dose | Frequency |
|---|---|---|---|
| Mild-moderate infection | 50 mg/kg | 420 mg | Once daily |
| Severe infection/pneumonia | 75 mg/kg | 630 mg | Once daily |
| Very severe infection | 100 mg/kg | 840 mg | Once daily or divided q12h |
| Meningitis | 100 mg/kg | 840 mg | Once daily or divided q12h |
Key Clinical Considerations
Once-daily dosing is appropriate for this patient because:
- Ceftriaxone has an extended half-life (6-8 hours) that permits once-daily administration 4, 5, 6
- The long half-life is particularly advantageous in pediatric patients 5
- Once-daily dosing has been extensively validated in severe community-acquired pneumonia in children 7
Common pitfalls to avoid:
- Do not underdose severe infections—use 75-100 mg/kg/day, not the lower 50 mg/kg range 1
- Do not exceed 2 grams daily for non-meningeal infections in this age group 2
- Do not infuse faster than 60 minutes in neonates and young infants 2
- For meningitis, consider divided dosing (every 12 hours) rather than once-daily to maintain CSF concentrations 1
Duration of therapy: