Amoxicillin 400mg/5ml Dosage for a 28-Pound Child
For a 28-pound (12.7 kg) child, administer 3.6 mL of amoxicillin 400mg/5ml suspension twice daily (every 12 hours) for mild to moderate infections, or 7.2 mL twice daily for severe infections or high-resistance areas. 1
Weight-Based Calculation
The child weighs 28 pounds = 12.7 kg 1
Standard dosing (mild to moderate infections): 45 mg/kg/day divided every 12 hours 1, 2
- Calculation: 12.7 kg × 45 mg/kg/day = 571.5 mg/day
- Per dose: 285.75 mg twice daily
- Volume: 3.6 mL of 400mg/5ml suspension twice daily 1
High-dose regimen (severe infections or high pneumococcal resistance): 90 mg/kg/day divided every 12 hours 1, 3
- Calculation: 12.7 kg × 90 mg/kg/day = 1,143 mg/day
- Per dose: 571.5 mg twice daily
- Volume: 7.2 mL of 400mg/5ml suspension twice daily 1
Indication-Specific Dosing Algorithm
Use the standard 45 mg/kg/day regimen (3.6 mL twice daily) for: 1, 2
- Uncomplicated respiratory tract infections
- Skin and soft tissue infections
- Genitourinary tract infections
- Group A Streptococcal pharyngitis (though 50-75 mg/kg/day is preferred for strep throat) 1
Use the high-dose 90 mg/kg/day regimen (7.2 mL twice daily) for: 1, 3
- Community-acquired pneumonia in areas with >10% penicillin-resistant S. pneumoniae 1
- Children <2 years old with pneumonia 1
- Recent antibiotic exposure within the past 30 days 1
- Children attending daycare 1
- Severe infections requiring aggressive treatment 1
- Acute bacterial sinusitis in children <2 years 1
Administration Instructions
- Give at the start of a meal to minimize gastrointestinal intolerance 2
- Shake the suspension well before each use 2
- The suspension can be placed directly on the child's tongue or mixed with formula, milk, fruit juice, water, or cold drinks and taken immediately 2
- Store reconstituted suspension in the refrigerator (preferred but not required) and discard after 14 days 2
Treatment Duration and Monitoring
- Continue treatment for 7-10 days for most respiratory infections 1, 3
- For pneumonia specifically, treat for 10 days 1
- For Group A Streptococcal infections, treat for 10 days to prevent acute rheumatic fever 1, 2
- Continue therapy for a minimum of 48-72 hours beyond symptom resolution 2
- Children should show clinical improvement within 48-72 hours; if no improvement occurs, reevaluation and consideration of resistant pathogens or alternative diagnoses is necessary 1, 3
Critical Considerations and Common Pitfalls
Avoid these common errors:
- Do not use age-based dosing instead of weight-based dosing, as this leads to inaccurate dosing 4
- Do not underdose in areas with high pneumococcal resistance—this contributes to treatment failure and resistance development 1, 5
- Do not use the 875 mg tablet formulation in children <40 kg, as it is not appropriate for pediatric dosing 2
For β-lactamase-producing organisms (H. influenzae, M. catarrhalis), amoxicillin-clavulanate (Augmentin) at 90 mg/kg/day of the amoxicillin component should be used instead of amoxicillin alone 1, 6
Maximum daily dose: Do not exceed 4,000 mg/day of amoxicillin regardless of weight 1