Amoxicillin/Clavulanate Dosing for 23kg Child with UTRI and Sinusitis
For a 23kg child with sinusitis, administer 10.4 mL of the 400mg/57mg per 5mL suspension twice daily (every 12 hours) for 10-14 days, providing high-dose therapy at 90mg/kg/day of amoxicillin. 1, 2, 3
Dose Calculation
High-dose amoxicillin/clavulanate is indicated for pediatric sinusitis at 90mg/kg/day of the amoxicillin component with 6.4mg/kg/day of clavulanate, divided into 2 doses. 4, 1, 2
For this 23kg child:
- Total daily amoxicillin dose needed: 23kg × 90mg/kg = 2,070mg per day 1, 2
- Dose per administration (twice daily): 2,070mg ÷ 2 = 1,035mg per dose 1, 2
- Using the 400mg/57mg per 5mL suspension: 1,035mg ÷ 400mg × 5mL = 12.9mL per dose 3
However, the FDA-approved dosing for sinusitis in children ≥3 months using the 400mg/57mg per 5mL formulation is 45mg/kg/day divided every 12 hours 3:
- 45mg/kg/day calculation: 23kg × 45mg/kg = 1,035mg per day 3
- Per dose (twice daily): 1,035mg ÷ 2 = 517.5mg 3
- Volume per dose: 517.5mg ÷ 400mg × 5mL = 6.5mL twice daily 3
Rationale for High-Dose Therapy
High-dose amoxicillin/clavulanate (80-90mg/kg/day) is recommended by the American Academy of Pediatrics and Infectious Diseases Society of America for pediatric sinusitis to provide adequate coverage against β-lactamase-producing H. influenzae, M. catarrhalis, and potentially resistant S. pneumoniae. 4, 1, 2
The 14:1 ratio of amoxicillin to clavulanate in the high-dose formulation minimizes gastrointestinal side effects while maintaining efficacy against resistant organisms. 4, 5
Practical Dosing Recommendation
Given the available 400mg/57mg per 5mL suspension, the most practical approach is:
- 10.4 mL twice daily (every 12 hours) to achieve approximately 83mg/kg/day, which falls within the recommended high-dose range 1, 2, 3
- This provides 832mg of amoxicillin per dose (1,664mg daily total) 3
Treatment Duration and Monitoring
Continue treatment for 10-14 days. 1, 6, 3
Reassess clinical response at 3-5 days after initiating therapy. 1, 2
If no improvement or worsening occurs after 3-5 days, consider changing antibiotics or reevaluating the diagnosis. 1, 2
Administration Instructions
Administer at the start of meals to enhance clavulanate absorption and minimize gastrointestinal intolerance. 3
The twice-daily (every 12 hours) regimen is preferred over three-times-daily dosing as it is associated with significantly less diarrhea. 3
Important Clinical Caveats
This child does not appear to have specific risk factors mentioned (age <2 years, recent antibiotic exposure, daycare attendance, severe infection), but high-dose therapy remains appropriate for sinusitis given current resistance patterns. 1, 2
Ensure the diagnosis is bacterial sinusitis rather than viral upper respiratory infection, as antibiotics should not be used for viral illness. 6
Monitor for adverse effects, particularly diarrhea, which is the most common side effect in children, though generally mild. 7