Augmentin Dosing for a 6.58 kg Infant
For a 6.58 kg infant, administer Augmentin 200 mg/5 mL suspension at 3 mL twice daily (providing 90 mg/kg/day of amoxicillin component), given for 10 days. 1, 2, 3
Weight-Based Calculation
The recommended dose is 90 mg/kg/day of the amoxicillin component divided into 2 doses for infants ≥3 months with bacterial infections requiring Augmentin. 1, 2, 3
For a 6.58 kg infant: 6.58 kg × 90 mg/kg/day = 592 mg total daily dose, administered as 296 mg twice daily. 1, 3
Using the 200 mg/5 mL suspension (which contains 40 mg amoxicillin per mL), each dose requires approximately 7.4 mL to deliver 296 mg. 3
However, the FDA-approved dosing table for the high-dose 600 mg/42.9 mg per 5 mL formulation recommends 3 mL twice daily for an 8 kg infant, which would be the closest weight bracket for your 6.58 kg patient. 3
Critical Formulation Considerations
The 200 mg/5 mL suspension you have is NOT the high-dose formulation. The high-dose formulation is 600 mg/42.9 mg per 5 mL, which provides the optimal 14:1 ratio of amoxicillin to clavulanate. 2, 3, 4
The 200 mg/5 mL suspension contains 28.5 mg clavulanate per 5 mL, providing a 7:1 ratio, whereas the high-dose formulation contains 42.9 mg clavulanate per 5 mL with a 14:1 ratio. 3, 4
These formulations are NOT interchangeable according to FDA labeling. 3
Practical Dosing with Your Available Formulation
If you must use the 200 mg/5 mL suspension you have:
To achieve 90 mg/kg/day (592 mg total daily), administer 7.4 mL twice daily (296 mg per dose). 1, 2
This provides adequate amoxicillin dosing but delivers more clavulanate than the optimal high-dose formulation, potentially increasing gastrointestinal side effects (particularly diarrhea). 2, 5, 4
Age Restriction and Safety
For infants <3 months with suspected serious bacterial infection, intravenous regimens (ampicillin + gentamicin or cefotaxime) are strongly preferred over oral Augmentin. 2
If this infant is <3 months old, specialist consultation is mandatory before prescribing oral Augmentin. 2
Indication-Specific Guidance
For community-acquired pneumonia in infants <5 years: 90 mg/kg/day in 2 doses for 10 days. 1, 2, 6
For acute otitis media in infants <2 years: 90 mg/kg/day in 2 doses for 10 days, particularly if there are risk factors (recent antibiotic use, daycare attendance, incomplete H. influenzae type b vaccination). 2, 4
For β-lactamase-producing organisms (H. influenzae, M. catarrhalis): 90 mg/kg/day in 2 doses is the preferred regimen. 1, 2
Administration and Monitoring
Administer at the start of meals to minimize gastrointestinal intolerance and enhance clavulanate absorption. 3
Shake suspension well before each use. 3
Clinical improvement should occur within 48-72 hours; if no improvement or worsening occurs, reevaluation is necessary. 1, 2
Complete the full 10-day course even if symptoms improve earlier. 1, 2
Common Pitfalls to Avoid
Do not use adult dosing or age-based dosing—always calculate based on weight for infants and children <40 kg. 1, 2
Do not substitute different Augmentin formulations without recalculating the dose, as they contain different amounts of clavulanate and are not interchangeable. 3
Do not underdose—subtherapeutic dosing promotes antimicrobial resistance and treatment failure, particularly with penicillin-resistant S. pneumoniae. 1, 2, 7
Verify the suspension concentration on the bottle label before dispensing to avoid dosing errors. 2
Adverse Effects
The most common adverse effect is diarrhea (occurring in approximately 9-27% of patients), with the high-dose 14:1 ratio formulation causing significantly less diarrhea than older formulations. 1, 2, 5, 8
Other common effects include nausea, vomiting, diaper dermatitis, and rash. 1, 2
The twice-daily regimen improves adherence and reduces adverse effects compared to three-times-daily dosing. 5, 8