What is the recommended dose of cephazolin (a cephalosporin antibiotic) for pediatric patients?

Recommended Dosage of Cefazolin in Pediatric Patients

For pediatric patients over 1 month of age, the recommended dose of cefazolin is 75 mg/kg every 8 hours (q8h). 1

Dosage Guidelines by Age Group

Neonates (under 1 month)

• Safety and efficacy not established in premature infants and neonates 2
• Use is not recommended in these populations

Infants and Children (over 1 month)

• Standard dosing: 75 mg/kg every 8 hours 1
• Total daily dosage range: 25-50 mg/kg/day divided into 3-4 equal doses for mild to moderate infections 2
• Can be increased to 100 mg/kg/day for severe infections 2

Dosing Based on Severity

• Mild to moderate infections: 25-50 mg/kg/day divided into 3-4 doses 2
• Severe infections: Up to 100 mg/kg/day divided into 3-4 doses 2

Administration Guidelines

Preparation and Administration

• For intramuscular (IM) injection: Reconstitute with Sterile Water for Injection

  • 500 mg vial: Add 2 mL (resulting in 225 mg/mL concentration)
  • 1 g vial: Add 2.5 mL (resulting in 330 mg/mL concentration) 2

• For intravenous (IV) administration:

  • Direct (bolus) injection: Further dilute with approximately 5 mL Sterile Water for Injection
  • Inject slowly over 3-5 minutes 2

Dosage Adjustments for Renal Impairment

Pediatric Patients with Renal Impairment

• Mild to moderate impairment (CrCl 70-40 mL/min): 60% of normal daily dose every 12 hours
• Moderate impairment (CrCl 40-20 mL/min): 25% of normal daily dose every 12 hours
• Severe impairment (CrCl 20-5 mL/min): 10% of normal daily dose every 24 hours 2
• Always administer an initial loading dose appropriate to the severity of infection 2

Clinical Considerations

Advantages of the q8h Dosing Schedule

• The 75 mg/kg q8h dosing regimen provides adequate serum concentrations to effectively treat common pathogens while reducing the frequency of administration compared to q6h dosing 1
• Less frequent dosing may improve medication adherence while maintaining efficacy 3

Common Pitfalls and Caveats

• Do not confuse cefazolin with other cephalosporins (such as cephalexin, cefotaxime) which have different dosing recommendations
• Always verify the correct preparation and concentration when administering to pediatric patients
• For severe infections, consider using the higher end of the dosing range
• Always administer a loading dose before implementing reduced dosing for renal impairment 2

Weight-Based Dosing Examples

For 25 mg/kg/day divided into 3 doses (q8h):

• 4.5 kg child: 40 mg per dose
• 9 kg child: 75 mg per dose
• 13.6 kg child: 115 mg per dose
• 18.1 kg child: 150 mg per dose
• 22.7 kg child: 190 mg per dose 2

For 50 mg/kg/day divided into 3 doses (q8h):

• 4.5 kg child: 75 mg per dose
• 9 kg child: 150 mg per dose
• 13.6 kg child: 225 mg per dose
• 18.1 kg child: 300 mg per dose
• 22.7 kg child: 375 mg per dose 2

By following these evidence-based dosing guidelines, clinicians can effectively treat pediatric infections while minimizing the risk of adverse effects and optimizing treatment outcomes.