Is it appropriate to give a 9-year-old child with fever and cough amoxicillin (amoxicillin) 500 mg twice daily (bid)?

Amoxicillin 500 mg BID is NOT appropriate for a 9-year-old child with fever and cough

The correct dose for a 9-year-old child with presumed community-acquired pneumonia is 90 mg/kg/day divided into 2 doses, NOT a fixed 500 mg twice daily. 1, 2

Weight-Based Dosing is Essential in Pediatric Patients

• Pediatric amoxicillin dosing must be calculated based on the child's weight, not prescribed as fixed adult doses. 2, 3
• The average 9-year-old weighs approximately 25-30 kg, which would require 1,125-1,350 mg twice daily (90 mg/kg/day ÷ 2 doses) for presumed bacterial pneumonia. 1, 2
• Prescribing only 500 mg BID (1,000 mg/day total) would provide only 33-40 mg/kg/day for an average-sized 9-year-old—this is significantly underdosed and inadequate for treating pneumococcal pneumonia, especially penicillin-resistant strains. 1, 2

Guideline-Recommended Dosing for Children ≥5 Years with Respiratory Infections

For outpatient treatment of presumed bacterial pneumonia in children ≥5 years old:

• High-dose amoxicillin: 90 mg/kg/day divided into 2 doses (maximum 4 g/day) is the first-line recommendation. 1, 2
• This high-dose regimen is specifically designed to overcome penicillin-resistant Streptococcus pneumoniae, the most common bacterial cause of community-acquired pneumonia. 4
• For mild infections in areas with low pneumococcal resistance, 45 mg/kg/day in 2 doses may be considered, but 90 mg/kg/day is preferred for empiric therapy. 2

Critical Prescribing Requirements

Every antibiotic prescription for children should include:

• The child's current weight in kilograms 5
• The calculated daily dose in mg/kg/day 5
• The number of divided doses per day 5
• The duration of therapy (typically 10 days for pneumonia) 2
• The specific indication for the prescription 5

Clinical Monitoring

• Children on appropriate amoxicillin therapy should demonstrate clinical improvement within 48-72 hours. 1, 2
• If no improvement occurs or the child deteriorates within this timeframe, further investigation is necessary and consideration should be given to atypical pathogens (requiring macrolide addition). 1, 2
• Treatment duration for pneumonia should be 10 days minimum. 2

Common Pitfall to Avoid

The most critical error is using fixed adult doses (like 500 mg BID) in pediatric patients rather than calculating weight-based dosing. 2, 5 This leads to systematic underdosing in children, particularly for serious infections like pneumonia, and contributes to treatment failure and antibiotic resistance. 1, 6