What is the recommended oral dose of cefadroxil (cephalosporin antibiotic) for a 10-year-old boy weighing approximately 32 kilograms with leg cellulitis?

Oral Cefadroxil Dosing for Pediatric Leg Cellulitis

For a 10-year-old boy weighing 32 kg with leg cellulitis, administer cefadroxil 30 mg/kg/day divided into two doses (every 12 hours), which equals 480 mg twice daily or approximately 500 mg (one teaspoon of 500 mg/5 mL suspension) twice daily for 10 days. 1

Weight-Based Calculation

• The FDA-approved dosing for skin and skin structure infections in children is 30 mg/kg/day in equally divided doses every 12 hours 1
• For this 32 kg patient: 32 kg × 30 mg/kg/day = 960 mg total daily dose 1
• Divided into two doses: 480 mg every 12 hours 1
• Using the 500 mg/5 mL suspension, this translates to approximately 5 mL (one teaspoon) twice daily 1

Duration of Therapy

• Continue treatment for 10 days minimum to ensure adequate eradication of streptococcal pathogens, which are common in cellulitis 1
• The FDA label specifically emphasizes that beta-hemolytic streptococcal infections require at least 10 days of therapeutic dosing 1

Clinical Evidence Supporting This Regimen

• Cefadroxil at 30 mg/kg/day has demonstrated 94% clinical response rates in pediatric skin infections, with excellent bacteriologic eradication of Staphylococcus aureus (96%) and Streptococcus pyogenes 2
• The twice-daily dosing schedule improves compliance compared to more frequent dosing regimens, with 95% of patients completing the full medication course 2
• Clinical studies in children aged 1-18 years using this exact dosing (30 mg/kg/day) showed effectiveness in cellulitis and other pyodermas without significant adverse effects 3, 2

Administration Guidelines

• Cefadroxil may be given without regard to meals, though administering with food can reduce gastrointestinal side effects 1
• After reconstitution, store the suspension in the refrigerator, shake well before each use, and discard after 14 days 1
• The suspension does not require food for absorption, unlike some other antibiotics 3

Common Pitfalls to Avoid

• Do not underdose: Ensure the full 30 mg/kg/day is prescribed; lower doses may lead to treatment failure 1
• Do not shorten the duration: Completing less than 10 days increases risk of recurrence, particularly with streptococcal infections 1
• Monitor for treatment failure: If no improvement occurs within 48-72 hours, consider resistant organisms (particularly MRSA) and switch to alternative therapy 2, 4
• Verify renal function: In patients with impaired renal function, dosing adjustments are necessary, though this is uncommon in healthy 10-year-olds 1