Augmentin Dosing for a 22-kg Child
For a 22-kg child, give 10 mL of the 400 mg/57 mg per 5 mL suspension (or 600 mg/42.5 mg per 5 mL suspension) twice daily, which delivers 1,980 mg/day of amoxicillin—the high-dose regimen of 90 mg/kg/day recommended for most pediatric respiratory and ear infections. 1
Calculation and Formulation Selection
Weight-based calculation: 22 kg × 90 mg/kg/day = 1,980 mg amoxicillin total daily dose, divided into two doses of 990 mg each (approximately 1,000 mg per dose). 1
Volume per dose: Using the 400 mg/57 mg per 5 mL suspension (also called the 14:1 ratio formulation), each 5 mL contains 400 mg amoxicillin. To deliver 990 mg per dose: (990 mg ÷ 400 mg) × 5 mL = 12.4 mL per dose, which rounds to 10–12.5 mL twice daily. 1, 2
Alternative high-dose suspension: The 600 mg/42.5 mg per 5 mL formulation (Augmentin ES-600) delivers 600 mg amoxicillin per 5 mL. For 990 mg per dose: (990 mg ÷ 600 mg) × 5 mL = 8.25 mL per dose, which rounds to 8–8.5 mL twice daily. 1, 3
Practical recommendation: Prescribe 10 mL of 400/57 suspension twice daily or 8 mL of 600/42.5 suspension twice daily, both achieving the target 90 mg/kg/day amoxicillin dose. 1, 2
When High-Dose Therapy Is Indicated
High-dose amoxicillin-clavulanate (90 mg/kg/day amoxicillin + 6.4 mg/kg/day clavulanate in two divided doses) is the first-line regimen for children with any of the following risk factors: 1
- Age < 2 years (this child is likely in this category if presenting with acute otitis media or sinusitis). 1
- Daycare attendance. 1, 4
- Recent antibiotic use within the past 30 days. 1, 4
- Incomplete Haemophilus influenzae type b vaccination (< 3 injections). 1
- Geographic area with > 10% prevalence of penicillin-resistant Streptococcus pneumoniae. 1, 4
- Moderate-to-severe illness at presentation. 1
- Concurrent purulent acute otitis media or conjunctivitis (otitis-conjunctivitis syndrome). 1
The high-dose regimen achieves middle-ear fluid and lung tissue concentrations that overcome penicillin-resistant S. pneumoniae (MIC 2–4 µg/mL) and β-lactamase-producing H. influenzae and M. catarrhalis, with predicted clinical efficacy of 90–92%. 1, 5, 6
Treatment Duration and Monitoring
Duration: 10 days for acute otitis media, acute bacterial rhinosinusitis, and community-acquired pneumonia in children. 1, 2
Reassessment at 48–72 hours: Clinical improvement (reduced fever, pain, irritability) should be evident within 48–72 hours. If no improvement or worsening occurs, switch to an alternative antibiotic (e.g., ceftriaxone) or investigate for complications. 1
Critical Prescribing Pitfalls
Do not use the 125/31 or 250/62 suspensions for high-dose therapy—these formulations do not provide the 14:1 ratio needed to deliver 90 mg/kg/day amoxicillin with only 6.4 mg/kg/day clavulanate. Using these formulations at high doses would result in excessive clavulanate and significantly increased diarrhea (44% vs. 14% with the 14:1 ratio). 1, 3
Verify the suspension concentration before dispensing: The 400/57 per 5 mL and 600/42.5 per 5 mL suspensions are specifically designed for high-dose therapy. The older 125/31 and 250/62 suspensions are for standard-dose regimens only. 1, 2
Do not substitute tablets for suspension in young children: The 250/125 mg tablets contain a different amoxicillin-to-clavulanate ratio (2:1) than the high-dose suspensions (14:1) and are not interchangeable. 2
Administer at the start of meals: Absorption of clavulanate is enhanced when given with food, and gastrointestinal side effects (nausea, diarrhea) are minimized. 2
Tolerability of High-Dose Therapy
The 14:1 ratio formulation (90/6.4 mg/kg/day) causes significantly less diarrhea than older amoxicillin-clavulanate preparations (3:1 or 7:1 ratios) while maintaining equivalent or superior efficacy against resistant pathogens. 1, 7, 3
Common adverse effects include diarrhea (25% vs. 15% placebo) and diaper dermatitis (51% vs. 35% placebo), but these rates are lower than with standard-ratio formulations. 1, 6
Serious adverse events are rare (3.6% total adverse event rate in large postmarketing studies), and the high-dose formulation shows similar tolerability to conventional twice-daily dosing. 7