Maximum Amoxicillin Dosing in Pediatrics
The maximum recommended dose of amoxicillin in pediatric patients is 90 mg/kg/day, with an absolute maximum of 4 grams per day regardless of weight. 1
Dosing Guidelines Based on Indication
Community-Acquired Pneumonia
- Standard dosing: 90 mg/kg/day divided into 2 doses (or 45 mg/kg/day in 3 doses) 2, 1
- Maximum daily dose: 4 g/day 1
Lower Respiratory Tract Infections
- Mild/Moderate or Severe: 45 mg/kg/day divided every 12 hours or 40 mg/kg/day divided every 8 hours 2
- For penicillin-resistant S. pneumoniae (MICs ≥4.0 μg/mL), higher doses of ampicillin may be used (300-400 mg/kg/day) in parenteral form 2
Ear/Nose/Throat and Skin/Skin Structure Infections
- Mild/Moderate: 25 mg/kg/day divided every 12 hours or 20 mg/kg/day divided every 8 hours 3
- Severe: 45 mg/kg/day divided every 12 hours or 40 mg/kg/day divided every 8 hours 3
Age-Specific Considerations
Infants Less Than 12 Weeks (3 Months)
- Maximum dose: 30 mg/kg/day divided every 12 hours due to incompletely developed renal function 3
Children 3 Months and Older
- Standard dosing range: 40-90 mg/kg/day depending on severity and type of infection 2, 1, 3
- Dosing frequency: Either twice daily (BID) or three times daily (TID) depending on indication and severity 1
Renal Impairment Adjustments
For children weighing >40 kg with renal impairment:
- GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours (based on infection severity) 3
- GFR <10 mL/min: 500 mg or 250 mg every 24 hours (based on infection severity) 3
- Hemodialysis: 500 mg or 250 mg every 24 hours plus additional dose during and after dialysis 3
Special Considerations
Weight-Based Dosing Caveats
- For obese children, there is debate about whether to use actual body weight or ideal body weight for dosing calculations 4
- When calculated doses exceed the standard adult dose of 1500 mg/day, some clinicians cap the dose while others maintain weight-based dosing 4
Antibiotic Resistance Considerations
- Higher doses (90 mg/kg/day) are recommended in areas with high prevalence of penicillin-resistant S. pneumoniae 1, 5
- The standard 40 mg/kg/day dosing may be inadequate for resistant organisms, particularly during viral co-infection 5
Treatment Duration
- For most infections, treatment should continue for at least 48-72 hours beyond symptom resolution 3
- For Streptococcus pyogenes infections, minimum 10-day treatment is recommended to prevent acute rheumatic fever 3
- Recent evidence supports shorter 5-day courses for uncomplicated pneumonia 1, 6
Common Pitfalls to Avoid
- Underdosing: Using 40 mg/kg/day when 90 mg/kg/day is needed for resistant organisms
- Inappropriate frequency: Using TID dosing when BID dosing with the same total daily dose may improve adherence 7
- Failure to adjust for age: Not reducing dose for infants under 12 weeks
- Overlooking renal function: Not adjusting doses in patients with impaired renal function
- Arbitrary dose capping: Limiting doses in larger children without clinical justification
By following these evidence-based dosing guidelines, clinicians can optimize treatment efficacy while minimizing the risk of adverse effects and antimicrobial resistance.