Pediatric Amoxicillin Dose

Pediatric amoxicillin dosing

The usual amoxicillin dose in children is 40–50 mg/kg/day, split either every 12 hours or every 8 hours. When you're treating acute otitis media or acute bacterial sinusitis, guidelines push the dose up to a high-dose regimen of 80–90 mg/kg/day so it still reaches penicillin-non-susceptible Streptococcus pneumoniae. For GAS pharyngotonsillitis (Streptococcus pyogenes), give 50 mg/kg/day over 10 days, and a single daily dose works fine here. Example: a 15 kg child at 50 mg/kg/day comes to 750 mg/day → 375 mg every 12 h or 250 mg every 8 h. On the high-dose regimen that's 90 × 15 = 1350 mg/day.

Clinical context

You'll see it across pediatric infectious disease and primary care (APS/SUS) for otitis, sinusitis, community-acquired pneumonia, pharyngitis and urinary tract infections. It tends to be the first-line beta-lactam because it's well tolerated and covers pneumococcus. Lean on the Brazilian Society of Pediatrics (SBP) guidelines and the Ministry of Health protocols. Always ask about penicillin allergy before prescribing, and switch to a macrolide if the allergy is severe. Doses also need adjusting when kidney function is impaired.

FAQ

Every 8 or every 12 hours? Dosing 12/12 h is easier to stick to and works for most indications. Go with 8/8 h when the infection is severe or the daily dose is on the higher end.

When to use the high dose (80–90 mg/kg/day)? Mainly for acute otitis media and bacterial sinusitis. It matters more in children under 2, kids in daycare, or anyone who took antibiotics recently.

Treatment duration? Pharyngotonsillitis runs 10 days. Otitis is 5–10 days depending on the child's age and how bad it is. Either way, finish the whole course.