How the dose is calculated
Amoxicillin-clavulanate is dosed by its amoxicillin component in mg/kg/day, divided every 12 hours. The clavulanate component (a beta-lactamase inhibitor) is fixed by the formulation's ratio, not calculated separately — so always dispense the exact product/ratio the dose was calculated against.
Typical dosing by indication
| Indication | Dose | Frequency | Max |
|---|---|---|---|
| Standard-dose | 25 mg/kg/day (amox.) | every 12h (2×/day) | 1750 mg/day |
| High-dose | 90 mg/kg/day (amox.) | every 12h (2×/day) | 4000 mg/day |
All doses above refer to the amoxicillin component only — the clavulanate dose is fixed by the specific product's amoxicillin:clavulanate ratio (e.g. 7:1, 14:1). Do not substitute a different ratio product without re-checking the clavulanate dose against its own maximum.
Clinical use
- Adding clavulanate (a beta-lactamase inhibitor) extends amoxicillin's spectrum to cover many beta-lactamase-producing organisms that plain amoxicillin cannot — used when a resistant organism is suspected or confirmed.
- High-dose regimens (90 mg/kg/day of the amoxicillin component) are commonly used for acute otitis media and sinusitis where drug-resistant Streptococcus pneumoniae is a concern.
- The clavulanate component is more often responsible for GI side effects (diarrhoea) than the amoxicillin component — taking with food can help.
- Different product ratios (e.g. 7:1 vs 14:1 amoxicillin:clavulanate) exist specifically to allow higher amoxicillin doses without exceeding the clavulanate maximum — always match the formulation to the intended regimen.
Frequently asked questions
Why is amoxicillin-clavulanate dosed by the amoxicillin component?
Because the amoxicillin component drives the antibacterial dose needed for the infection, while the clavulanate component is fixed by the product's ratio — so clinicians target the amoxicillin dose and the clavulanate follows automatically from the chosen formulation.
What does the clavulanate part actually do?
Clavulanate is a beta-lactamase inhibitor — it doesn't kill bacteria itself, but it blocks the enzyme some bacteria use to destroy amoxicillin, restoring amoxicillin's effectiveness against those resistant organisms.
Why does amoxicillin-clavulanate cause more stomach upset than plain amoxicillin?
The clavulanate component is more commonly associated with diarrhoea and GI upset than amoxicillin alone — taking the dose with food can help reduce this.
Can any co-amoxiclav suspension strength be used interchangeably?
No — different strengths (e.g. 228 mg/5 mL vs 400 mg/5 mL) usually have different amoxicillin:clavulanate ratios, so switching strength without recalculating can under- or over-dose the clavulanate component.
References
- American Academy of Pediatrics. Clinical Practice Guideline: Acute Otitis Media. Pediatrics. 2013.
- British National Formulary for Children (BNFc) — Co-amoxiclav.
- European Society for Paediatric Infectious Diseases (ESPID) — Community-Acquired Pneumonia Guidelines.