Cefazolin Dosing for Pediatric Patients
For children over 1 month of age, administer cefazolin at 75 mg/kg every 8 hours for most infections, with total daily doses ranging from 25-100 mg/kg/day divided into 3-4 doses depending on infection severity. 1, 2
Standard Dosing by Infection Severity
Mild to Moderate Infections
- Total daily dose: 25-50 mg/kg/day divided into 3-4 equal doses 2
- This translates to approximately 10-20 mg/lb of body weight per day 2
- Effective for most mild to moderately severe infections 2
Severe Infections
- Total daily dose may be increased to 100 mg/kg/day (45 mg/lb) for severe infections 2
- The guideline-recommended dose for catheter-related infections is 75 mg/kg every 8 hours 1
Specific Pathogen Considerations
For methicillin-susceptible Staphylococcus aureus (MSSA) infections:
- Preferred parenteral dose: 150 mg/kg/day divided every 8 hours 1
- This higher dose is specifically recommended for pneumonia and serious staphylococcal infections 1
Age-Specific Restrictions
Critical caveat: Cefazolin is NOT recommended for premature infants and neonates, as safety has not been established in this population. 2 The dosing recommendations apply only to children over 1 month of age 1
Renal Impairment Adjustments
For pediatric patients with renal dysfunction, dose reductions are necessary 2:
- Mild impairment (CrCl 70-40 mL/min): 60% of normal daily dose divided every 12 hours 2
- Moderate impairment (CrCl 40-20 mL/min): 25% of normal daily dose divided every 12 hours 2
- Severe impairment (CrCl 20-5 mL/min): 10% of normal daily dose every 24 hours 2
- All reduced dosing applies after an initial loading dose appropriate to infection severity 2
Practical Dosing Examples
The FDA label provides specific weight-based calculations 2:
For 25 mg/kg/day regimen (mild infections):
- 10 lb (4.5 kg) child: 40 mg every 8 hours
- 20 lb (9 kg) child: 75 mg every 8 hours
- 50 lb (22.7 kg) child: 190 mg every 8 hours
For 50 mg/kg/day regimen (moderate infections):
- 10 lb (4.5 kg) child: 75 mg every 8 hours
- 20 lb (9 kg) child: 150 mg every 8 hours
- 50 lb (22.7 kg) child: 375 mg every 8 hours
Administration Considerations
Intravenous Administration
- Direct bolus injection: Dilute reconstituted solution with approximately 5 mL Sterile Water for Injection and inject slowly over 3-5 minutes 2
- Intermittent infusion: Dilute in 50-100 mL of compatible solution 2
Intramuscular Administration
- Reconstitute according to package instructions and inject into large muscle mass 2
- Pain on injection is infrequent with cefazolin 2
Special Clinical Scenarios
Surgical Prophylaxis
While the FDA label primarily addresses adult surgical prophylaxis, recent research suggests standard pediatric dosing (50 mg/kg every 4-6 hours) may be inadequate during cardiopulmonary bypass 3. In children undergoing cardiac surgery with CPB, consider higher or more frequent dosing, particularly in patients with good renal function and when targeting organisms with higher MICs 3.
Duration of Stability
Reconstituted cefazolin is stable for 24 hours at room temperature or 10 days under refrigeration (5°C) 2. Solutions may range from pale yellow to yellow without change in potency 2
Common Pitfalls to Avoid
- Do not use in neonates or premature infants - safety not established 2
- Do not underdose severe infections - use the full 100 mg/kg/day for life-threatening infections 2
- Do not forget loading dose in renal impairment - reduced maintenance doses should follow an appropriate loading dose 2
- Do not exceed adult maximum doses - while pediatric dosing is weight-based, consider adult dose caps for larger children