Amoxicillin dose for children: indications and weight-based dosing

The short answer: 40–90 mg/kg/day divided 2–3 times daily, depending on indication

Amoxicillin is a first-line antibiotic in pediatrics for susceptible infections including otitis media, streptococcal pharyngitis, community-acquired pneumonia, sinusitis, and uncomplicated urinary tract infections. Dosing depends on the infection:

• Standard dose: 40–45 mg/kg/day divided q12h or q8h
• High-dose (otitis media, resistant strep): 80–90 mg/kg/day divided q12h
• Maximum: 4 g/day (regardless of weight, for older children)

Is amoxicillin approved for children?

Yes — including neonates with adjusted dosing:

• Neonates 0–28 days: 20–30 mg/kg/day divided q12h (under neonatologist)
• Infants 1–24 months: 30–45 mg/kg/day divided q12h (standard) or 80–90 mg/kg/day q12h (high-dose)
• Children 2–12 years: same weight-based dosing as infants
• Adolescents 12+: adult dosing 500 mg q8h or 875 mg q12h

Dosing by indication

| Indication | Dose | Duration | |---|---|---| | Acute otitis media | 80–90 mg/kg/day divided q12h | 5–10 days | | Strep pharyngitis | 50 mg/kg once daily (max 1 g) | 10 days | | Community-acquired pneumonia | 45 mg/kg q12h (max 4 g/day) | 5–7 days | | Sinusitis | 45 mg/kg q12h | 7–10 days | | UTI (uncomplicated) | 25–50 mg/kg/day divided q8h | 5–10 days |

Formulations for children

• Suspension 125 mg/5 mL — for toddlers, usually q12h
• Suspension 250 mg/5 mL — most common, q12h or q8h
• Suspension 400 mg/5 mL — for higher doses (otitis)
• Chewable tablets 125/250 mg — age 3+ who can chew
• Capsules 250/500 mg — adolescents

Shake the suspension well before each dose. Refrigerate after reconstitution, discard after 14 days.

Warnings specific to pediatrics

• Not penicillin-allergic: confirm no prior reaction; rash is common but usually benign (often morbilliform, not true allergy)
• Mononucleosis rash: amoxicillin in a child with EBV mononucleosis causes a widespread non-allergic rash — inform the prescriber
• Diarrhea is common (up to 10%); severe or bloody diarrhea warrants review for C. difficile
• Complete the full course even if symptoms resolve early
• Do not share with siblings who appear to have the same infection — always see a pediatrician
• Reconstituted suspension: refrigerate and discard after 14 days

Clinical sources

• American Academy of Pediatrics "Red Book" — Infectious Diseases chapter.
• IDSA Clinical Practice Guideline — Community-Acquired Pneumonia in Infants and Children (2011, updated 2023).
• NICE NG79 "Otitis media (acute): antimicrobial prescribing."
• BNF for Children — amoxicillin monograph.

Bottom line

Amoxicillin is safe, effective, and well-tolerated in children at weight-based doses tailored to the infection type. Standard dose is 40–45 mg/kg/day divided q12h; high-dose for otitis media is 80–90 mg/kg/day. Always complete the course, even if your child feels better.

Do not start, adjust, or share amoxicillin without a pediatrician's prescription. Antibiotic stewardship protects your child and future patients.