Amoxicillin Dosing for a 30 kg Child
For a 30 kg child, the appropriate dose of amoxicillin is 45 mg/kg/day in divided doses every 12 hours, which equals 1350 mg per day or 675 mg per dose twice daily.
Dosage Calculation Based on Weight
According to the FDA drug label for amoxicillin, the recommended dosage for pediatric patients aged 3 months and older weighing less than 40 kg is:
- For mild/moderate infections: 25 mg/kg/day in divided doses every 12 hours or 20 mg/kg/day in divided doses every 8 hours
- For severe infections or lower respiratory tract infections: 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours 1
For a 30 kg child:
- Mild/moderate infections (twice daily dosing): 25 mg/kg/day = 750 mg/day = 375 mg per dose
- Severe infections (twice daily dosing): 45 mg/kg/day = 1350 mg/day = 675 mg per dose
Administration Guidelines
- Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 1
- Treatment should continue for a minimum of 48 to 72 hours beyond symptom resolution
- For Streptococcus pyogenes infections, a minimum of 10 days of treatment is recommended 1
Dosing Based on Formulation
If using oral suspension:
- For 125 mg/5 mL concentration: 27 mL per dose (twice daily)
- For 250 mg/5 mL concentration: 13.5 mL per dose (twice daily)
Important Considerations
- The American Academy of Pediatrics recommends amoxicillin at 90 mg/kg/day divided into 2 doses (or 45 mg/kg/day in 3 doses) for conditions like pneumonia 2
- For infections caused by penicillin-resistant organisms, higher dosing may be required
- Recent evidence suggests that twice-daily dosing (b.i.d.) is a feasible alternative to three-times-daily (t.i.d.) dosing, which may improve compliance 3
Common Pitfalls to Avoid
- Underdosing larger children: Recent research shows that larger children often receive lower than recommended doses per kilogram 4
- Exceeding maximum adult doses in heavier children
- Inadequate treatment duration, especially for streptococcal infections
- Failure to adjust dosing based on severity of infection
Remember that amoxicillin dosing should be adjusted based on the severity of infection, with higher doses (45 mg/kg/day) recommended for severe or lower respiratory tract infections.