Amoxicillin Dosing for Dental Infection in an 8-Year-Old
For an 8-year-old child with a dental infection, prescribe amoxicillin 40-50 mg/kg/day divided into two doses (every 12 hours) for 5-7 days, with a maximum daily dose not exceeding 1500 mg/day (750 mg twice daily) for this age group. 1, 2
Weight-Based Dosing Algorithm
- Calculate the dose based on the child's actual weight, not age alone, as this provides more accurate dosing and reduces the risk of under- or overdosing 2, 3
- For an average 8-year-old weighing approximately 25-30 kg:
- Administer at the start of meals to minimize gastrointestinal side effects 1
Dosing Rationale for Dental Infections
- Dental (odontogenic) infections in children typically respond well to standard-dose amoxicillin, as they are usually caused by susceptible oral flora including streptococci and anaerobes 4
- Twice-daily dosing (every 12 hours) is preferred over three-times-daily because it improves compliance without compromising efficacy, and reduces the incidence of diarrhea 2, 5
- The 40-50 mg/kg/day range maintains adequate plasma concentrations above the MIC for common oral pathogens for >50% of the dosing interval 5
Treatment Duration and Monitoring
- Prescribe for 5-7 days based on clinical severity and response 4
- Continue treatment for 48-72 hours beyond symptom resolution to ensure bacterial eradication 1
- If no improvement occurs within 48-72 hours, consider switching to amoxicillin-clavulanate (45 mg/kg/day of amoxicillin component divided twice daily) to cover beta-lactamase producing organisms 4, 6
Prescription Clarity
Write the prescription with the following specific details to prevent dosing errors 2:
- Total daily dose in mg/kg/day
- Individual dose amount in mg per administration
- Frequency (every 12 hours, twice daily)
- Duration of therapy (5-7 days)
- Child's current weight
- Indication (dental infection)
Common Pitfalls to Avoid
- Do not use age-band dosing alone without considering the child's weight, as this leads to significant underdosing in 5.8% of children and potential overdosing in 0.5% 3
- Do not prescribe three-times-daily dosing when twice-daily is equally effective and better tolerated 2, 5
- Do not exceed the pediatric maximum of 1500 mg/day for children under 40 kg, even if weight-based calculations suggest higher doses 1
- Ensure the prescription specifies liquid suspension concentration (typically 250 mg/5 mL or 400 mg/5 mL) to prevent dispensing errors 1
Safety Considerations
- Most common adverse effects are mild gastrointestinal disturbances, particularly diarrhea, which occurs less frequently with twice-daily dosing 4, 6
- Reconstituted suspension must be discarded after 14 days; refrigeration is preferable but not required 1
- Instruct caregivers to shake the suspension well before each use 1