How the dose is calculated
Amoxicillin is dosed in mg/kg/day, split across the selected regimen's dosing frequency. The standard regimen covers most mild-to-moderate infections; the high-dose regimen is used where resistant Streptococcus pneumoniae is more likely (e.g. acute otitis media, sinusitis) or in higher-risk patients, per paediatric and adult prescribing guidance.
Typical dosing by indication
| Indication | Dose | Frequency | Max |
|---|---|---|---|
| Standard-dose | 40 mg/kg/day | every 8h (3×/day) | 1500 mg/day |
| High-dose | 90 mg/kg/day | every 12h (2×/day) | 4000 mg/day |
Clinical use
- Amoxicillin is first-line for many common infections — acute otitis media, community-acquired pneumonia in children, streptococcal pharyngitis, and uncomplicated UTI — because of its narrow spectrum and excellent oral bioavailability.
- High-dose regimens are preferred where drug-resistant Streptococcus pneumoniae is a concern, since higher tissue concentrations can overcome reduced penicillin-binding-protein affinity.
- Not appropriate for infections likely caused by beta-lactamase-producing organisms — amoxicillin-clavulanate is used instead in that setting.
- Renal impairment requires dose-interval adjustment; confirm against local renal dosing guidance for significant CrCl reduction.
Frequently asked questions
Is amoxicillin dosed by weight in children?
Yes — paediatric amoxicillin dosing is calculated in mg per kg of body weight per day, then divided across the prescribed frequency, unlike the fixed adult doses used once a child reaches adult weight.
What's the difference between standard-dose and high-dose amoxicillin?
High-dose amoxicillin (around 80–90 mg/kg/day) is used when drug-resistant Streptococcus pneumoniae is more likely, such as in acute otitis media or sinusitis, or in children under 2 or with recent antibiotic exposure — it isn't needed for every infection.
Can amoxicillin be given with food?
Yes — amoxicillin absorption is not significantly affected by food, so it can be given with or without meals, which can help reduce stomach upset.
What if a dose of amoxicillin is missed?
Give the missed dose as soon as remembered unless it's almost time for the next one — in that case skip it and resume the normal schedule. Don't double up doses.
References
- Bradley JS, et al. The Management of Community-Acquired Pneumonia in Infants and Children (PIDS/IDSA). Clin Infect Dis. 2011.
- American Academy of Pediatrics. Clinical Practice Guideline: The Diagnosis and Management of Acute Otitis Media. Pediatrics. 2013.
- British National Formulary for Children (BNFc) — Amoxicillin.