What is the recommended dose of amoxicillin (amoxicillin) for a 9-year-old child weighing 120 pounds (54.4 kilograms)?

Amoxicillin Dosing for a 9-Year-Old Child Weighing 120 Pounds (54.4 kg)

For a 9-year-old child weighing 120 pounds (54.4 kg), the recommended amoxicillin dose is 45 mg/kg/day in 2 divided doses, which equals approximately 2,450 mg per day (1,225 mg twice daily). 1

Dosing Calculation

• The FDA-approved dosing for amoxicillin in pediatric patients weighing ≥40 kg follows adult dosing guidelines 1
• For mild to moderate infections: 45 mg/kg/day in divided doses every 12 hours 1
• For severe infections: 90 mg/kg/day in divided doses every 12 hours 1
• Calculation for this 54.4 kg child:
  • Standard dose: 45 mg/kg/day × 54.4 kg = 2,448 mg/day (rounded to 2,450 mg/day)
  • Divided into two doses: 1,225 mg twice daily 1

Dosing Considerations Based on Indication

• For respiratory tract infections (such as pneumonia):

  • Preferred dosing is 45 mg/kg/day in 2 doses for mild to moderate infections 2
  • For more severe infections or areas with high pneumococcal resistance, higher dosing of 90 mg/kg/day may be warranted 2

• For Group A Streptococcal infections:

  • Recommended dose is 50-75 mg/kg/day in 2 doses 2
  • Treatment should continue for a minimum of 10 days to prevent acute rheumatic fever 1

• For otitis media:

  • Higher dosing of 90 mg/kg/day in 2 doses is recommended, especially in areas with drug-resistant Streptococcus pneumoniae 3
  • This higher dose ensures adequate middle ear fluid penetration 3

Administration Guidelines

• Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 1
• For oral suspension formulations, shake well before using 1
• Treatment should continue for a minimum of 48 to 72 hours beyond symptom resolution 1

Important Considerations

• Twice-daily dosing (every 12 hours) is preferred over three-times-daily dosing for improved adherence while maintaining similar efficacy 4, 5
• For children with pneumonia, studies show that twice-daily dosing with higher per-dose amounts provides comparable drug exposure to three-times-daily dosing 5
• Recent evidence suggests that shorter treatment durations (3 days) may be as effective as longer durations (7 days) for uncomplicated infections, with similar rates of adverse events and antimicrobial resistance 6

Potential Adverse Effects

• Most common adverse effects include gastrointestinal disturbances (diarrhea, nausea, vomiting) 2
• Rash, urticaria, and other hypersensitivity reactions may occur 2
• Diarrhea is generally less frequent with twice-daily than with three-times-daily treatment 7

Dosing in Special Circumstances

• For patients with severe renal impairment (GFR <30 mL/min), dose adjustment is necessary 1
• For recurrent or persistent otitis media after amoxicillin failure, high-dose amoxicillin/clavulanate may be considered 7

Remember that this child's weight (54.4 kg) places them in the adult dosing category per FDA guidelines, but pediatric-specific considerations should still be applied when determining the appropriate dose.