Augmentin Dosing for an 8-Year-Old Patient Weighing 38.6 kg
For this 8-year-old patient weighing 38.6 kg, the recommended Augmentin dose depends on the infection severity: for mild to moderate respiratory tract infections, prescribe 45 mg/kg/day (approximately 1,737 mg/day) divided into two doses, which translates to roughly 870 mg twice daily; for severe infections or areas with high pneumococcal resistance, prescribe 90 mg/kg/day (approximately 3,474 mg/day) divided into two doses, which translates to roughly 1,737 mg twice daily. 1, 2
Weight-Based Dosing Algorithm
Since this patient weighs 38.6 kg (less than 40 kg), dosing should be calculated based on weight rather than using standard adult doses 2:
For Mild to Moderate Infections
- Standard dose: 45 mg/kg/day of the amoxicillin component divided every 12 hours 1, 2
- For this 38.6 kg patient: 38.6 kg × 45 mg/kg = 1,737 mg/day total
- Practical dosing: approximately 870 mg twice daily 1
- This provides adequate coverage for most susceptible pathogens including Streptococcus pneumoniae, Haemophilus influenzae (β-lactamase producing), and Moraxella catarrhalis 1
For Severe Infections or High-Resistance Areas
- High-dose regimen: 90 mg/kg/day of the amoxicillin component divided every 12 hours 1, 3
- For this 38.6 kg patient: 38.6 kg × 90 mg/kg = 3,474 mg/day total
- Practical dosing: approximately 1,737 mg twice daily 1
- This higher dose is specifically indicated for:
Maximum Dose Considerations
- The maximum daily dose should not exceed 4,000 mg (4 g) of the amoxicillin component per day, regardless of weight 1, 2
- For this patient, even the high-dose regimen (3,474 mg/day) remains well below the maximum threshold 1
Indication-Specific Guidance
Respiratory Tract Infections (Pneumonia, Sinusitis)
- Mild to moderate: 45 mg/kg/day divided every 12 hours 1, 2
- Severe or high resistance: 90 mg/kg/day divided every 12 hours 1, 3
- Treatment duration: typically 7-10 days, with pneumonia requiring 10 days 1
Skin and Soft Tissue Infections
- Standard dose: 45 mg/kg/day divided every 12 hours 2
- Severe infections: 45 mg/kg/day divided every 12 hours or 40 mg/kg/day divided every 8 hours 2
Ear/Nose/Throat Infections
- Mild to moderate: 45 mg/kg/day divided every 12 hours 2
- For patients with recent antibiotic use (within 4-6 weeks): use high-dose 90 mg/kg/day regimen to cover β-lactamase-producing organisms 1
Critical Dosing Considerations
The choice between standard and high-dose regimens should be based on:
- Severity of infection - severe infections warrant 90 mg/kg/day 1
- Local antimicrobial resistance patterns - areas with >10% penicillin-resistant pneumococcus require higher dosing 1
- Recent antibiotic exposure - use within past 30 days necessitates 90 mg/kg/day 1
- Daycare attendance - increases risk of resistant organisms 1
Administration and Monitoring
- Administer at the start of meals to minimize gastrointestinal intolerance 2
- Children on appropriate therapy should demonstrate clinical improvement within 48-72 hours 1
- If no improvement occurs within 48-72 hours, reevaluation and further investigation are necessary 1
- Complete the full course of antibiotics as prescribed, even if symptoms improve before completion 1
Common Pitfalls to Avoid
- Do not underdose severe infections - always use 90 mg/kg/day for life-threatening infections or documented resistant organisms 1
- Do not use adult dosing for children under 40 kg - weight-based dosing is essential for this age group 2
- Do not prescribe the 875 mg tablet formulation for patients under 40 kg - this is specifically contraindicated in the FDA labeling 2
- Ensure adequate hydration and monitor for gastrointestinal adverse effects, particularly diarrhea 4, 5