What is the recommended dose of Ancef (cefazolin) for a 10-year-old male weighing 63 pounds with a facial laceration?

Cefazolin (Ancef) Dosing for Pediatric Facial Laceration

For a 10-year-old male weighing 63 pounds (28.6 kg) with a facial laceration, administer cefazolin 25 mg/kg/dose intravenously every 8 hours, which equals approximately 715 mg per dose (can round to 750 mg for practical administration). 1, 2

Weight-Based Calculation

• Convert weight: 63 pounds = 28.6 kg 1
• Standard pediatric dosing: For children >1 month of age with skin and soft tissue infections, the recommended dose is 25-50 mg/kg/day divided into 3-4 doses 1, 3
• For this patient: Using 25 mg/kg per dose every 8 hours = 28.6 kg × 25 mg/kg = 715 mg per dose 1
• Practical rounding: Round to 750 mg per dose for ease of administration using standard vial concentrations 3

Dosing Frequency and Route

• Administer every 8 hours (three times daily) for adequate tissue levels 1, 3
• Intravenous route preferred for facial lacerations to ensure rapid therapeutic levels and prevent potential wound infections 2
• Alternative: If IV access is problematic, intramuscular administration is acceptable at the same dose 3

Clinical Rationale

• Cefazolin is the preferred first-generation cephalosporin for skin and soft tissue infections, providing excellent coverage against methicillin-susceptible Staphylococcus aureus (MSSA) and Streptococcus species, the most common pathogens in traumatic facial lacerations 1, 2
• Facial wounds carry higher cosmetic significance, making appropriate antibiotic prophylaxis particularly important to prevent infection and scarring 2
• The 25 mg/kg dose represents the lower end of the pediatric range (25-50 mg/kg/day) and is appropriate for prophylaxis or mild-to-moderate infections 1, 3

Duration of Therapy

• For uncomplicated facial lacerations: A short course of 24-48 hours is typically sufficient if the wound is properly cleaned and closed 2
• Extend to 5-7 days only if signs of established infection develop (erythema, purulent drainage, fever) 2

Administration Technique

• For IV bolus: Reconstitute with Sterile Water for Injection, then further dilute with approximately 5 mL and inject slowly over 3-5 minutes 3
• For IV infusion: Dilute in 50-100 mL of normal saline or 5% dextrose and infuse over 30 minutes 3
• Shake vial well after reconstitution and inspect for particulate matter 3

Important Caveats

• Penicillin allergy: If the patient has a documented penicillin allergy, assess the type and severity before administering cefazolin, as cross-reactivity occurs in approximately 1-3% of cases with IgE-mediated reactions 4
• Renal function: No dose adjustment needed for normal renal function in this age group 1, 3
• Pain on injection: Cefazolin causes minimal pain with intramuscular injection compared to other cephalosporins 5, 6

Common Pitfalls to Avoid

• Do not underdose: Using adult fixed dosing (e.g., 1 gram) without weight-based calculation may result in subtherapeutic levels in smaller children 1
• Do not extend therapy unnecessarily: Prolonged antibiotic courses beyond clinical need contribute to antimicrobial resistance 2
• Do not substitute vancomycin routinely: Reserve vancomycin for documented MRSA or true beta-lactam allergy, as cefazolin provides superior coverage for typical skin flora 1, 7