Maximum Dose of Amoxicillin for an 8-Year-Old Child
The maximum daily dose of amoxicillin for an 8-year-old child is 4 grams (4000 mg) per day, regardless of weight or indication. 1, 2, 3
Weight-Based Dosing Framework
For an 8-year-old child, dosing should be calculated based on body weight rather than age alone, with the following considerations:
Standard Dosing Ranges
For mild to moderate infections (such as uncomplicated respiratory tract infections, skin infections, or urinary tract infections): The typical dose is 45 mg/kg/day divided into 2 doses (or 40 mg/kg/day divided into 3 doses), with a maximum of 4 grams per day 1, 2, 3
For severe infections or high-resistance areas (including pneumonia in regions with high pneumococcal resistance): The recommended dose is 90 mg/kg/day divided into 2 doses, with the same maximum ceiling of 4 grams per day 1, 2
Practical Calculation Example
For an average 8-year-old weighing approximately 25-30 kg:
- At 90 mg/kg/day: This would calculate to 2250-2700 mg/day, well below the 4-gram maximum 1
- For a heavier child weighing 45 kg or more: At 90 mg/kg/day, the calculation would exceed 4 grams, but the dose must be capped at the 4-gram maximum 1, 2
Critical Dosing Considerations
The 4-gram daily maximum is an absolute ceiling that should never be exceeded, even when weight-based calculations suggest a higher dose 1, 2, 3. This safety limit applies to all pediatric patients regardless of:
- Severity of infection
- Type of infection
- Local resistance patterns
- Body weight
Common Pitfalls to Avoid
- Do not exceed 4 grams daily even if the child weighs more than 44 kg and the 90 mg/kg calculation suggests a higher dose 1, 2
- Ensure proper dosing intervals: The 90 mg/kg/day regimen should be divided into 2 doses (given every 12 hours), not 3 doses, to maintain adequate serum concentrations 1, 2
- Consider renal function: Children with severe renal impairment (GFR <30 mL/min) require dose reduction and should not receive doses exceeding 500 mg every 12 hours 3
Indication-Specific Guidance
The evidence supports higher dosing (90 mg/kg/day up to 4 g/day maximum) specifically for:
- Community-acquired pneumonia in areas with high rates of penicillin-resistant Streptococcus pneumoniae 1, 2
- Acute otitis media when resistant organisms are suspected 4
- Any severe bacterial infection requiring aggressive treatment 1, 2
Lower dosing (45 mg/kg/day) remains appropriate for uncomplicated infections with susceptible organisms 1, 2.