Appropriate Amoxicillin Dosage for an 11-Year-Old
For an 11-year-old child, the appropriate dosage of amoxicillin depends on the indication, with standard dosing ranging from 45-90 mg/kg/day divided into 2-3 doses, with the specific dose determined by the severity and type of infection being treated. 1, 2
General Dosing Guidelines
- For an 11-year-old (who typically weighs more than 40 kg), dosing can follow either weight-based or adult dosing schedules depending on the child's actual weight 2
- For children weighing less than 40 kg, weight-based dosing should be used 2
- Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 2
Dosing Based on Infection Type
Respiratory Tract Infections
- For mild to moderate respiratory infections: 45 mg/kg/day divided into 2 doses 1
- For severe respiratory infections or in areas with high pneumococcal resistance: 90 mg/kg/day divided into 2 doses 1
- For lower respiratory tract infections: 45 mg/kg/day divided into 2 doses (every 12 hours) or 40 mg/kg/day divided into 3 doses (every 8 hours) 2
Streptococcal Infections
- For Group A Streptococcal infections (including strep throat): 50-75 mg/kg/day divided into 2 doses 3, 1
- Treatment should continue for at least 10 days for any Streptococcus pyogenes infection to prevent acute rheumatic fever 2
Ear/Nose/Throat, Skin/Skin Structure, Genitourinary Tract Infections
- Mild/Moderate: 25 mg/kg/day divided into 2 doses (every 12 hours) or 20 mg/kg/day divided into 3 doses (every 8 hours) 2
- Severe: 45 mg/kg/day divided into 2 doses (every 12 hours) or 40 mg/kg/day divided into 3 doses (every 8 hours) 2
Treatment Duration
- For most bacterial infections: Continue treatment for 48-72 hours beyond symptom resolution 2
- For respiratory infections: Typically 7-10 days 1
- For Group A Streptococcal infections: Minimum 10 days to prevent acute rheumatic fever 2
- Recent evidence suggests that shorter courses (3 days) may be as effective as longer courses (7 days) for community-acquired pneumonia, with similar rates of antibiotic retreatment and adverse events 4, 5
Special Considerations
- For community-acquired pneumonia, recent trials suggest that lower-dose amoxicillin (35-50 mg/kg/day) is non-inferior to higher doses (70-90 mg/kg/day) 4
- For uncomplicated community-acquired pneumonia in outpatient settings, a 5-day course may be as effective as a 10-day course 6
- For strep throat, even a single dose of amoxicillin (50 mg/kg) has been shown to rapidly reduce bacterial load, with 91% of children having no detectable Group A Streptococci within 12-23 hours 7
Formulation Considerations
- Amoxicillin is available as oral suspension and tablets 2
- For oral suspension, proper reconstitution is essential - follow specific instructions for adding the correct amount of water based on the suspension strength 2
- Shake oral suspension well before using 2
- Reconstituted suspension must be discarded after 14 days 2
- Refrigeration is preferable but not required 2
Potential Adverse Effects
- Most common: Gastrointestinal disturbances (diarrhea, nausea, vomiting) 1
- Hypersensitivity reactions: Rash, urticaria 1
By following these evidence-based dosing guidelines, clinicians can ensure appropriate amoxicillin treatment for 11-year-old patients while minimizing the risk of treatment failure and antimicrobial resistance.