Dosing Calculation for Puncture Wound in 19-kg Child
For a 19-kg child with a puncture wound, administer 6.8 mL of the 125 mg/5 mL amoxicillin-clavulanate suspension every 12 hours.
Calculation Breakdown
For puncture wounds (animal or human bites), amoxicillin-clavulanate is the first-line oral antibiotic to cover both aerobic and anaerobic bacteria 1. The FDA-approved dosing for the 125 mg/5 mL suspension formulation is based on the amoxicillin component 2.
Standard Dosing for Bite Wounds
- Target dose: 45 mg/kg/day of amoxicillin divided every 12 hours (for more severe infections including bite wounds) 2
- For this 19-kg child:
- Total daily dose = 45 mg/kg/day × 19 kg = 855 mg/day
- Per dose (every 12 hours) = 855 mg ÷ 2 = 427.5 mg per dose
Volume Calculation
- The 125 mg/5 mL suspension contains 25 mg of amoxicillin per mL
- Required volume = 427.5 mg ÷ 25 mg/mL = 17.1 mL per dose
However, this calculation appears to reference the wrong formulation. If you're using "125 every 12 hrs" referring to the 125 mg/31.25 mg per 5 mL formulation (the lower concentration suspension):
- Each 5 mL contains 125 mg amoxicillin
- For 427.5 mg needed: (427.5 mg ÷ 125 mg) × 5 mL = 17.1 mL per dose
Alternative High-Concentration Formulation
If using the 200 mg/28.5 mg per 5 mL or 400 mg/57 mg per 5 mL formulations (which provide higher amoxicillin concentrations and are preferred for the every 12-hour regimen 2):
- 400 mg/5 mL formulation: (427.5 mg ÷ 400 mg) × 5 mL = 5.3 mL per dose
Clinical Context
Bite wounds require amoxicillin-clavulanate specifically because the clavulanate component inhibits beta-lactamases produced by common bite wound pathogens including Pasteurella multocida (animal bites) and oral anaerobes 1. The combination provides coverage against both aerobic and anaerobic bacteria that colonize animal and human mouths.
Duration
- Preemptive therapy: 3-5 days for puncture wounds, especially those involving the hand, face, or with moderate to severe injury 1
- Tetanus prophylaxis should also be considered 1
Important Caveat
The every 12-hour regimen is preferred over every 8-hour dosing as it's associated with significantly less diarrhea while maintaining equivalent efficacy 2. Administer at the start of meals to enhance clavulanate absorption and minimize GI intolerance 2.