Augmentin Dosing for a 35 kg Child
For a 35 kg child with normal renal function, prescribe Augmentin at 90 mg/kg/day of the amoxicillin component divided into 2 doses (1,575 mg twice daily), which translates to approximately 20 mL of the 200 mg/5 mL suspension twice daily or 16 mL of the 250 mg/5 mL suspension twice daily.
Weight-Based Dose Calculation
The high-dose regimen of 90 mg/kg/day is the standard recommendation for most pediatric infections requiring Augmentin, particularly respiratory tract infections, acute otitis media, and community-acquired pneumonia 1, 2.
For a 35 kg child: 90 mg/kg/day × 35 kg = 3,150 mg total daily dose of the amoxicillin component, administered as 1,575 mg every 12 hours 1, 2.
This high-dose formulation provides a 14:1 ratio of amoxicillin to clavulanate (90 mg/kg amoxicillin with 6.4 mg/kg clavulanate), which minimizes gastrointestinal side effects while maintaining efficacy against β-lactamase-producing organisms 2, 3.
Practical Suspension Volumes
Using 200 mg/5 mL suspension: approximately 39 mL per dose (round to 40 mL for practical administration) 1.
Using 250 mg/5 mL suspension: approximately 31.5 mL per dose (round to 32 mL) 2.
The 600 mg/5 mL high-dose formulation (Augmentin ES-600) would require approximately 13 mL per dose, offering more convenient dosing volumes 3, 4.
Indication-Specific Considerations
Respiratory Tract Infections
For community-acquired pneumonia, acute bacterial sinusitis, or acute otitis media, the 90 mg/kg/day regimen in 2 divided doses for 10 days is strongly recommended 1, 2.
This dosing achieves middle-ear and sinus fluid concentrations sufficient to overcome penicillin-resistant Streptococcus pneumoniae with MICs up to 2–4 mg/L 2, 3.
When High-Dose Is Mandatory
Use the 90 mg/kg/day regimen when any of these risk factors are present: recent antibiotic use within 30 days, daycare attendance, age <2 years, geographic area with >10% penicillin-resistant S. pneumoniae, or moderate-to-severe illness 2.
For β-lactamase-producing Haemophilus influenzae or Moraxella catarrhalis, Augmentin (not plain amoxicillin) at 90 mg/kg/day is required 1, 2.
Treatment Duration and Monitoring
Complete a full 10-day course for most respiratory infections and acute otitis media 1, 2.
Clinical improvement should be evident within 48–72 hours; if no improvement or worsening occurs, reassess the diagnosis and consider atypical pathogens or complications 1, 2.
Continue therapy for at least 48–72 hours after complete resolution of fever and symptoms 1.
Maximum Dose Limits
The maximum single dose is 2,000 mg per administration, regardless of weight 2.
The maximum daily dose is 4,000 mg (4 g) of the amoxicillin component per day 1, 2.
For this 35 kg child, the calculated dose of 1,575 mg twice daily (3,150 mg/day total) is well below both limits 1, 2.
Common Pitfalls to Avoid
Do not use standard-dose regimens (40–45 mg/kg/day) when treating infections likely caused by resistant organisms or when risk factors are present, as this leads to treatment failure 2.
Verify the suspension concentration before calculating volume—the 125/31 mg/5 mL formulation is for younger children, while 250/62 mg/5 mL or higher concentrations are appropriate for this weight 2.
Do not use the 4:1 or 7:1 ratio formulations for high-dose therapy; only the 14:1 ratio (90/6.4 mg/kg/day) provides adequate amoxicillin while minimizing clavulanate-related diarrhea 2, 3, 4.
Do not prescribe Augmentin for viral infections; ensure bacterial infection is confirmed or highly suspected before initiating antibiotics 2.
Alternative for Penicillin Allergy
For non-anaphylactic penicillin allergy, use second- or third-generation cephalosporins (cefdinir, cefuroxime) 1.
For IgE-mediated (Type I) allergy, use clindamycin (10–20 mg/kg/day in 3 doses) or azithromycin (12 mg/kg once daily for 5 days), acknowledging inferior efficacy compared to β-lactams 1, 2.