Co-amoxiclav 457 mg/5ml Dosing by Age
For co-amoxiclav 457 mg/5ml suspension (equivalent to 400 mg amoxicillin + 57 mg clavulanic acid per 5 mL), the standard dosing is 5 mL twice daily for children aged 1-10 years, providing approximately 45 mg/kg/day of amoxicillin in two divided doses. 1
Dosing Table by Age Range
| Age Range | Volume per Dose | Frequency | Total Daily Volume |
|---|---|---|---|
| 1-2 years | 5 mL | Twice daily (q12h) | 10 mL/day |
| 3-4 years | 5 mL | Twice daily (q12h) | 10 mL/day |
| 5-6 years | 5 mL | Twice daily (q12h) | 10 mL/day |
| 7-8 years | 5 mL | Twice daily (q12h) | 10 mL/day |
| 9-10 years | 5 mL | Twice daily (q12h) | 10 mL/day |
Rationale and Key Considerations
The FDA-approved dosing for the 400 mg/57 mg per 5 mL formulation is 45 mg/kg/day divided every 12 hours for otitis media, sinusitis, lower respiratory tract infections, and more severe infections 1. This twice-daily regimen is specifically recommended because it is associated with significantly less diarrhea compared to three-times-daily dosing 1.
For less severe infections, the dose can be reduced to 25 mg/kg/day every 12 hours, which would translate to approximately 2.5-3 mL twice daily for younger children, though the standard 5 mL dose remains appropriate for most community-acquired infections 1.
Important Clinical Caveats
- Administer at the start of meals to enhance clavulanate absorption and minimize gastrointestinal intolerance 1
- The q12h (twice-daily) regimen is strongly preferred over q8h (three-times-daily) dosing due to better tolerability 1
- This formulation contains aspartame and should not be used in phenylketonuric patients 1
- Reconstituted suspension must be refrigerated and discarded after 10 days 1
Weight-Based Dosing Alternative
If precise weight-based dosing is needed for severe infections or immunocompromised patients, use 45 mg/kg/day (based on amoxicillin component) divided into two doses. For a typical child:
- 1-2 years (10-12 kg): 225-270 mg per dose = approximately 2.5-3 mL twice daily
- 3-4 years (14-16 kg): 315-360 mg per dose = approximately 4 mL twice daily
- 5-6 years (18-20 kg): 405-450 mg per dose = approximately 5 mL twice daily
- 7-8 years (22-26 kg): 495-585 mg per dose = approximately 5-7 mL twice daily
- 9-10 years (28-32 kg): 630-720 mg per dose = approximately 7-9 mL twice daily
However, the standard 5 mL twice-daily dose is appropriate and FDA-approved for all children in the 1-10 year age range for most indications 1.
Guideline Context
British guidelines for pandemic influenza previously recommended age-based dosing of co-amoxiclav 125/31 suspension (5 mL three times daily for ages 1-6 years) 2, and the British Thoracic Society guidelines for community-acquired pneumonia recommended similar age-stratified dosing 3. However, the current FDA-approved formulation of 400/57 mg per 5 mL with twice-daily dosing supersedes these older recommendations and provides superior coverage with better tolerability 1.