Ceftriaxone dosage in paediatrics
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Ceftriaxone in paediatrics is dosed at 50-100 mg/kg/day (max 4 g/day) for most infections, given once daily or divided every 12-24 hours, with higher doses for meningitis and neonatal infections. Let me pull the full details from the textbooks now.
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Good - I have the Red Book 2021 (the gold standard for paediatric infectious diseases) and other relevant sources. Let me read the key sections for detailed dosing.
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Excellent - the Red Book references Table 4.2 (neonatal) and Table 4.3 (nonneonatal) in "Tables of Antibacterial Drug Dosages." Let me retrieve those directly, along with Harriet Lane (the definitive paediatric drug reference).
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I need to find the actual Ceftriaxone entry in Harriet Lane. Let me search for it specifically.
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I found the Harriet Lane dosing. Now let me read the "continued" section and also get the Red Book's antibacterial drug dosage table for ceftriaxone.
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Ceftriaxone Dosage in Paediatrics
Ceftriaxone is a third-generation cephalosporin given IV or IM, with once- or twice-daily dosing making it highly practical in paediatric practice.
Age-Based Dosing
Neonates (<28 days)
Important: Ceftriaxone is generally avoided in neonates <28 days old due to the risk of precipitation of ceftriaxone-calcium salt in lungs and kidneys (fatal cases reported in preterm and full-term neonates). It is also contraindicated in hyperbilirubinaemia (displaces bilirubin from albumin). Prefer cefotaxime in this age group.
If no alternative is available (e.g., congenital syphilis treatment when penicillin/cefotaxime unavailable):
- Congenital syphilis (alternative only): 50-75 mg/kg/day IV Q24 hr (with close clinical and serologic follow-up and specialist consultation)
- Gonococcal ophthalmia/prophylaxis: 25-50 mg/kg/dose IM/IV x 1; max dose 250 mg
Infants (>1 month) and Children
| Indication | Dose | Frequency | Max Dose |
|---|---|---|---|
| Mild/moderate infections | 50-75 mg/kg/24 hr | Q12-24 hr IV/IM | 2 g/24 hr |
| Severe infections / Meningitis | 100 mg/kg/24 hr | Q12 hr IV/IM | 2 g/dose; 4 g/24 hr |
| Penicillin-resistant pneumococci (non-CNS) | 80-100 mg/kg/24 hr | Q12-24 hr | 2 g/dose; 4 g/24 hr |
| Acute otitis media (single-dose) | 50 mg/kg | x1 IM/IV | 1 g |
| Acute otitis media (persistent/relapse) | 50 mg/kg | Q24 hr x 3 doses IM/IV | 1 g/dose |
| Lyme disease | 50-75 mg/kg/dose | Once daily IV | 2 g/dose |
| Endocarditis prophylaxis (dental/URT) | 50 mg/kg IV/IM | 30-60 min before procedure | 1 g |
- The Harriet Lane Handbook, 23rd ed.
Condition-Specific Dosing (from Multiple Sources)
Bacterial Meningitis
- 100 mg/kg/day IV, divided Q12 hr - max 4 g/24 hr
- Combine with vancomycin empirically for suspected S. pneumoniae (pending susceptibility results)
- Ceftriaxone is avoided in neonatal meningitis (<28 days); use ampicillin + gentamicin instead
- For Haemophilus influenzae (Hib) meningitis: 75-100 mg/kg/day in two doses Q12 hr - Harrison's Principles of Internal Medicine, 22nd ed.
Meningococcal Infection
- 100 mg/kg/day IV (children 3 years to adulthood) - Rosen's Emergency Medicine
Bacteraemia / Occult Bacteraemia
- 50-100 mg/kg IM or IV (initial dose); followed by 100 mg/kg/day - Rosen's Emergency Medicine
- 80-100 mg/kg IV as a single daily dose has demonstrated efficacy, though Q12 hr remains standard
Pneumococcal Meningitis
- 50 mg/kg IV Q12 hr in children >3 months - Goldman-Cecil Medicine
- Use alongside vancomycin until susceptibility confirmed
UTI / Intra-abdominal Infections
- 50-75 mg/kg/24 hr IV Q12-24 hr (mild-moderate)
Congenital Syphilis (alternative agent only)
- 50-75 mg/kg/day IV Q24 hr for 10 days - Red Book 2021
Gonococcal Infections
- Uncomplicated gonorrhoea (adolescents <150 kg): 500 mg IM x 1
- Uncomplicated gonorrhoea (≥150 kg): 1 g IM x 1
Key Safety Considerations
- Neonates (<28 days): Avoid - risk of fatal ceftriaxone-calcium precipitates in lungs and kidneys. Contraindicated in hyperbilirubinaemia.
- IV calcium interaction: Do NOT administer simultaneously with IV calcium-containing solutions via Y-site at ANY age. Sequential administration requires thorough line flushing.
- Biliary effects: Can cause reversible cholelithiasis, gallbladder sludging, and jaundice (35-45% cleared via biliary route).
- Caution in: Penicillin allergy, hepatic + renal dysfunction (may need dose adjustment if both are impaired), gallbladder/biliary/pancreatic disease.
- Common side effects: Rash, injection-site pain, diarrhoea, transient LFT elevation.
- Lab interference: May cause false-positive urinary protein and urinary reducing substances (use enzymatic glucose oxidase tests, not Clinitest/Benedict's).
IM Administration
- Dilute with sterile water for injection OR 1% lidocaine to 250 or 350 mg/mL (250 mg/mL has lower incidence of injection-site reactions)
- Assess risk-benefit before using lidocaine in neonates
Summary Table
| Age Group | Standard Dose | Meningitis Dose |
|---|---|---|
| Neonate | Avoid (use cefotaxime) | Avoid |
| >1 month - child | 50-75 mg/kg/day Q12-24 hr | 100 mg/kg/day Q12 hr |
| Adult | 1-2 g Q12-24 hr | 2 g Q12 hr |
| Max dose | 2 g/24 hr | 4 g/24 hr |
Sources: The Harriet Lane Handbook (23rd ed.) - The Johns Hopkins Hospital | Red Book 2021 - AAP Committee on Infectious Diseases | Harrison's Principles of Internal Medicine (22nd ed.) | Rosen's Emergency Medicine | Goldman-Cecil Medicine
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