Amoxicillin Dosing for a 27-Pound 2-Year-Old
For a 2-year-old child weighing 27 pounds (12.3 kg), the recommended amoxicillin dose is 45 mg/kg/day divided into 2 doses (every 12 hours) for mild to moderate infections, which equals approximately 275 mg per dose or 6.9 mL of the 400mg/5mL suspension twice daily. 1, 2
Weight-Based Calculation
- Convert weight to kilograms: 27 pounds = 12.3 kg 1
- Standard dosing for mild to moderate infections: 45 mg/kg/day ÷ 2 doses = 22.5 mg/kg per dose 1, 2
- Calculated dose: 12.3 kg × 22.5 mg/kg = 276.75 mg per dose (approximately 275 mg twice daily) 1
- Volume using 400mg/5mL suspension: (275 mg ÷ 400 mg) × 5 mL = 3.4 mL twice daily 1
Indication-Specific Dosing Algorithm
For Mild to Moderate Respiratory Infections
- Dose: 45 mg/kg/day divided every 12 hours (approximately 3.4 mL of 400mg/5mL suspension twice daily) 1, 2
- This provides adequate coverage for Streptococcus pneumoniae, non-β-lactamase-producing Haemophilus influenzae, and Streptococcus pyogenes 2
For Severe Infections or High Pneumococcal Resistance Areas
- Dose: 90 mg/kg/day divided every 12 hours (approximately 6.9 mL of 400mg/5mL suspension twice daily) 1, 2
- Use this higher dose if the child has: 1, 2
- Recent antibiotic exposure within past 30 days
- Daycare attendance
- Age <2 years with severe infection
- Geographic area with >10% penicillin-resistant S. pneumoniae
For Group A Streptococcal Pharyngitis (Strep Throat)
- Dose: 50-75 mg/kg/day divided into 2 doses for 10 days, not exceeding 1000 mg per dose 1, 2
- For this 12.3 kg child: 615-920 mg daily (approximately 4-5.7 mL of 400mg/5mL suspension twice daily) 1
- Critical: Must complete full 10 days to prevent rheumatic fever 2, 3
Treatment Duration
- Respiratory infections: 7-10 days 1, 2
- Pneumonia specifically: 10 days 1, 2
- Group A Streptococcal infections: Mandatory 10 days to prevent rheumatic fever 2, 3
- Continue treatment for minimum 48-72 hours beyond symptom resolution 3
Administration Instructions
- Give at the start of meals to minimize gastrointestinal intolerance 3
- Shake suspension well before each use 3
- Can mix with formula, milk, fruit juice, water, or cold drinks if needed, but administer immediately after mixing 3
- Store reconstituted suspension in refrigerator (preferred but not required); discard after 14 days 3
Monitoring and Follow-Up
- Clinical improvement should occur within 48-72 hours of starting treatment 1, 2
- If no improvement by 72 hours, reassess diagnosis and consider alternative antibiotics 2
- Complete the full prescribed course even if symptoms improve earlier 1
Common Pitfalls to Avoid
- Do not use age-based dosing—always calculate based on weight in kg 1, 2
- Twice-daily dosing improves adherence compared to three-times-daily regimens 2
- For β-lactamase-producing organisms (H. influenzae, M. catarrhalis), amoxicillin alone is insufficient—use amoxicillin-clavulanate (Augmentin) instead 2
- Maximum daily dose is 4000 mg/day regardless of weight 2, 3