Amoxicillin Dosing Calculation for 49-Pound Child
For a child weighing 49 pounds (22.3 kg), the dose of amoxicillin at 40 mg/kg is 892 mg per day, which should be divided into 446 mg twice daily (every 12 hours).
Weight Conversion and Calculation
- 49 pounds = 22.3 kg 1
- 40 mg/kg × 22.3 kg = 892 mg total daily dose 1, 2
- Divided every 12 hours = 446 mg per dose, given twice daily 1, 2
Clinical Context for 40 mg/kg Dosing
The 40 mg/kg/day dose falls within the standard dosing range for mild to moderate infections 1, 2, 3:
- For mild to moderate respiratory tract infections: The American Academy of Pediatrics recommends 45 mg/kg/day divided every 12 hours, which is close to your requested 40 mg/kg dose 1, 2
- For severe infections or high pneumococcal resistance areas: 90 mg/kg/day divided every 12 hours is preferred 1, 2
Practical Dosing Considerations
The 40 mg/kg/day regimen (892 mg/day for this child) is appropriate for:
- Uncomplicated skin infections 1
- Genitourinary tract infections 1
- Mild respiratory infections in areas with low resistance 2
However, for community-acquired pneumonia or areas with >10% penicillin-resistant S. pneumoniae, you should increase to 90 mg/kg/day (approximately 2,000 mg/day for this child, or 1,000 mg twice daily) 1, 2
Administration Guidelines
- Timing: Give at the start of meals to minimize gastrointestinal intolerance 3
- Duration: Minimum 48-72 hours beyond symptom resolution; for Streptococcus pyogenes infections, treat for at least 10 days to prevent acute rheumatic fever 1, 3
- Monitoring: Clinical improvement should occur within 48-72 hours; if not, reevaluation is necessary 1, 2