Ceftriaxone Dosage in Paediatrics

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.

• 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

• 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

1. Neonates (<28 days): Avoid - risk of fatal ceftriaxone-calcium precipitates in lungs and kidneys. Contraindicated in hyperbilirubinaemia.
2. IV calcium interaction: Do NOT administer simultaneously with IV calcium-containing solutions via Y-site at ANY age. Sequential administration requires thorough line flushing.
3. Biliary effects: Can cause reversible cholelithiasis, gallbladder sludging, and jaundice (35-45% cleared via biliary route).
4. Caution in: Penicillin allergy, hepatic + renal dysfunction (may need dose adjustment if both are impaired), gallbladder/biliary/pancreatic disease.
5. Common side effects: Rash, injection-site pain, diarrhoea, transient LFT elevation.
6. 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