Co-amoxiclav Dosing for 3-Year-Old, 10kg Child
For a 3-year-old child weighing 10kg, the appropriate dose of co-amoxiclav 457mg/5ml suspension is 2.5ml twice daily (every 12 hours) for most infections, or 2.5ml three times daily (every 8 hours) for more severe infections such as otitis media, sinusitis, or lower respiratory tract infections.
Dosing Rationale
The 457mg/5ml formulation contains 400mg amoxicillin and 57mg clavulanic acid per 5ml. For this child:
Standard Dosing (Less Severe Infections)
- Target dose: 25 mg/kg/day of amoxicillin component divided every 12 hours 1
- Calculation: 10kg × 25mg/kg = 250mg/day total
- Per dose: 125mg amoxicillin per dose (twice daily)
- Volume: 1.56ml per dose ≈ 2.5ml twice daily (provides ~160mg amoxicillin per dose)
Higher Dosing (More Severe Infections)
- Target dose: 45 mg/kg/day of amoxicillin component divided every 12 hours 1
- Calculation: 10kg × 45mg/kg = 450mg/day total
- Per dose: 225mg amoxicillin per dose (twice daily)
- Volume: 2.8ml per dose ≈ 2.5ml twice daily (provides ~160mg amoxicillin per dose)
Alternatively, for severe infections:
- 40 mg/kg/day divided every 8 hours 1
- Calculation: 10kg × 40mg/kg = 400mg/day ÷ 3 doses = ~133mg per dose
- Volume: 2.5ml three times daily (provides ~160mg amoxicillin per dose)
Clinical Context
The twice-daily (q12h) regimen is preferred over three-times-daily dosing because it is associated with significantly less diarrhea 1. However, the 457mg/5ml formulation contains aspartame and should not be used in children with phenylketonuria 1.
Indications for Higher Dosing
Use 45mg/kg/day (or 40mg/kg/day q8h) for 2, 3, 1:
- Otitis media
- Sinusitis
- Lower respiratory tract infections
- More severe infections
- β-lactamase producing organisms (particularly Haemophilus influenzae)
Administration Guidelines
- Give at the start of meals to enhance clavulanate absorption and minimize gastrointestinal side effects 1
- Shake suspension well before each use 1
- Store reconstituted suspension under refrigeration 1
- Discard after 10 days 1
Important Caveats
Age Consideration
This child at 3 years old is well above the 12-week (3-month) threshold, so standard pediatric dosing applies rather than neonatal dosing 1.
Duration of Therapy
- Otitis media: 10 days recommended 1
- Other infections: Typically 5-10 days depending on clinical response 2, 3
- Monitor for clinical improvement within 48-72 hours 2
Alternative if β-lactamase NOT Suspected
If treating infections where β-lactamase-producing organisms are unlikely, plain amoxicillin at 90mg/kg/day (450mg/day = 225mg twice daily) would be preferred to minimize clavulanate-related side effects and reduce selection pressure for resistance 2, 3, 4.
Side Effects
The clavulanic acid component increases risk of: