Amoxicillin Dosing for Pediatric Patients
Recommended Dosage by Indication
For most pediatric respiratory tract infections including community-acquired pneumonia, prescribe amoxicillin 90 mg/kg/day divided into 2 doses (maximum 4 g/day), with treatment duration of 7-10 days. 1, 2
Respiratory Tract Infections
Mild to Moderate Infections:
- 45 mg/kg/day divided every 12 hours for mild respiratory infections 1
- This lower dose may be insufficient for areas with high pneumococcal resistance 1
Severe Infections or High-Resistance Areas:
- 90 mg/kg/day divided every 12 hours is the preferred regimen 1, 2
- The American Academy of Pediatrics and Infectious Diseases Society of America both recommend this higher dose for presumed bacterial pneumonia in children of all ages 2
- Maximum daily dose is 4 g/day regardless of weight 2
Group A Streptococcal Infections
- 50-75 mg/kg/day divided into 2 doses 1
- Must continue for at least 10 days to prevent acute rheumatic fever 3
Age-Specific Considerations
Infants Under 3 Months (12 weeks):
- Maximum 30 mg/kg/day divided every 12 hours due to immature renal function 3
- Treatment should continue for minimum 48-72 hours beyond symptom resolution 3
Children 3 Months and Older:
- Weight-based dosing is preferred over age-based dosing 1
- For children weighing ≥40 kg, use adult dosing regimens 3
Treatment Duration
Standard Duration:
- 7-10 days for most respiratory infections 1
- 10 days specifically for pneumonia 1
- At least 10 days for any Streptococcus pyogenes infection to prevent acute rheumatic fever 3
Recent evidence suggests 5-day courses may be adequate for uncomplicated community-acquired pneumonia with appropriate clinical monitoring 4, 5, though traditional guidelines still recommend 7-10 days 1.
When to Use Amoxicillin-Clavulanate Instead
Switch to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component in 2 doses) if: 1, 2, 6
- Incomplete Haemophilus influenzae type b vaccination (fewer than 3 doses) 6
- Concurrent purulent acute otitis media 1
- β-lactamase producing organisms suspected 2, 6
- Child under 5 years with presumed bacterial pneumonia in certain clinical contexts 6
Clinical Monitoring
Expected Response:
- Children should show clinical improvement within 48-72 hours of starting therapy 1, 2
- If no improvement occurs within this timeframe, reevaluation and possible treatment change are necessary 1, 2
Important Prescribing Details
What to Include on Every Prescription: 7
- Total daily dose in mg/kg/day
- Number of divided doses per day
- Duration of therapy in days
- Clinical indication
- Child's current weight
Common Pitfalls to Avoid
Underdosing in Heavier Children:
- Primary care physicians frequently prescribe lower-than-recommended doses in older, heavier children 8
- Some practitioners inappropriately cap doses at standard adult doses (1500 mg/day) even when weight-based dosing would exceed this 8
- Always calculate the full weight-based dose up to the maximum of 4 g/day 2
Inadequate Duration:
- Stopping antibiotics when symptoms improve but before completing the full course increases resistance risk 1
- Complete the full prescribed course even if symptoms resolve early 1
Viral Coinfection:
- Amoxicillin middle ear fluid penetration is significantly reduced during viral coinfection 9
- This supports the use of higher doses (75-90 mg/kg/day) rather than the older standard of 40 mg/kg/day 9
Renal Impairment Dosing
For children ≥3 months and >40 kg with severe renal impairment: 3
- GFR 10-30 mL/min: 250-500 mg every 12 hours
- GFR <10 mL/min: 250-500 mg every 24 hours
- Hemodialysis: 250-500 mg every 24 hours, with additional dose during and after dialysis
Administration Tips
- Give at the start of meals to minimize gastrointestinal intolerance 3
- Oral suspension can be mixed with formula, milk, fruit juice, water, or cold drinks if needed, but must be consumed immediately 3
- Shake suspension well before each use 3
- Refrigeration is preferable but not required; discard after 14 days 3