What is the appropriate pediatric dosing of Augmentin (amoxicillin/clavulanate) based on the child's weight, infection severity, age (including infants ≤3 months), and renal function?

Augmentin Dosing for Pediatric Patients

For most pediatric infections, use 45 mg/kg/day of the amoxicillin component divided every 12 hours, but escalate to 90 mg/kg/day divided every 12 hours for severe infections, resistant pathogens, or high-risk patients, with an absolute maximum of 4000 mg/day regardless of weight. 1, 2, 3

Age-Specific Dosing Framework

Neonates and Infants <3 Months

• The FDA-approved dose is 30 mg/kg/day divided every 12 hours based on the amoxicillin component, using the 125 mg/5 mL oral suspension (the 200 mg/5 mL formulation has limited experience in this age group). 3

Infants and Children ≥3 Months to <40 kg

Standard-Dose Regimen (Less Severe Infections):

• 25 mg/kg/day divided every 12 hours using the 200 mg/5 mL or 400 mg/5 mL suspension. 3
• Alternatively, 20 mg/kg/day divided every 8 hours using the 125 mg/5 mL or 250 mg/5 mL suspension. 3

High-Dose Regimen (Severe Infections or Resistant Pathogens):

• 45 mg/kg/day divided every 12 hours using the 200 mg/5 mL or 400 mg/5 mL suspension for mild-to-moderate respiratory infections. 1, 3
• 90 mg/kg/day divided every 12 hours (with 6.4 mg/kg/day clavulanate) for severe infections, providing a 14:1 amoxicillin-to-clavulanate ratio. 1, 2, 4

Children ≥40 kg

• Dose according to adult recommendations: one 500 mg/125 mg tablet every 12 hours for standard infections, or one 875 mg/125 mg tablet every 12 hours for severe respiratory infections. 3
• Do NOT use the 250 mg/125 mg tablets until the child weighs at least 40 kg due to different amoxicillin-to-clavulanate ratios. 3

Indication-Specific Dosing

Acute Otitis Media

• 90 mg/kg/day divided every 12 hours for 10 days is the preferred regimen, especially for children <2 years, bilateral AOM in children 6-23 months, or recent antibiotic use within 30 days. 4, 3, 5
• The high-dose formulation achieves middle ear fluid concentrations adequate to overcome penicillin-resistant S. pneumoniae (MICs 2-4 mg/L) and β-lactamase-producing H. influenzae and M. catarrhalis. 4, 5
• Twice-daily dosing is associated with significantly less diarrhea (7.2% vs 10.7%) and better compliance (82.8% vs 73.3%) compared to three-times-daily dosing. 3, 6

Community-Acquired Pneumonia

• For children <5 years: 90 mg/kg/day divided every 12 hours for 10 days. 1, 4
• For children ≥5 years: 90 mg/kg/day divided every 12 hours (maximum 4000 mg/day) for 10 days. 1, 4
• Use amoxicillin-clavulanate specifically for children with incomplete H. influenzae type b vaccination or concurrent purulent acute otitis media. 1, 4

Acute Bacterial Sinusitis

• 45 mg/kg/day divided every 12 hours for children ≥2 years without risk factors. 1
• 80-90 mg/kg/day divided every 12 hours for children <2 years, daycare attendance, or recent antibiotic use. 1

Group A Streptococcal Infections (Scarlet Fever, Pharyngitis)

• 50-75 mg/kg/day divided every 12 hours for 10 days, not exceeding 1000 mg per dose. 1

High-Risk Factors Requiring 90 mg/kg/day Dosing

Use the high-dose regimen (90 mg/kg/day) when ANY of the following are present: 1, 4

• Age <2 years
• Daycare attendance
• Recent antibiotic exposure within the past 30 days
• Incomplete H. influenzae type b vaccination (<3 doses)
• Geographic area with >10% penicillin-resistant S. pneumoniae
• Severe illness at presentation (high fever, marked symptoms)
• Treatment failure after 48-72 hours on standard-dose therapy

Renal Impairment Adjustments

• GFR 10-30 mL/min: 500 mg/125 mg or 250 mg/125 mg every 12 hours (depending on severity). 3
• GFR <10 mL/min: 500 mg/125 mg or 250 mg/125 mg every 24 hours. 3
• Hemodialysis: 500 mg/125 mg or 250 mg/125 mg every 24 hours, with an additional dose during and at the end of dialysis. 3
• Do NOT use the 875 mg/125 mg dose if GFR <30 mL/min. 3

Treatment Duration and Monitoring

• Standard duration: 7-10 days for most respiratory infections; 10 days specifically for pneumonia and acute otitis media. 1, 2, 3
• Clinical improvement should occur within 48-72 hours—if no improvement or worsening occurs, reevaluate for resistant pathogens, atypical organisms, or complications. 1, 4
• Fever typically resolves within 24-48 hours for pneumococcal infections, though cough may persist longer. 1

Critical Dosing Considerations and Common Pitfalls

• The absolute maximum amoxicillin dose is 4000 mg/day regardless of weight. 1, 2
• Do NOT substitute two 250 mg/125 mg tablets for one 500 mg/125 mg tablet—they contain different amounts of clavulanate and are not equivalent. 3
• Do NOT substitute the 250 mg/125 mg tablet for the 250 mg/62.5 mg chewable tablet—they contain different clavulanate amounts (125 mg vs 62.5 mg). 3
• Verify the suspension concentration (125/31,250/62,200/28.5, or 400/57 mg per 5 mL) before calculating volume to avoid dosing errors. 4
• Administer at the start of meals to enhance clavulanate absorption and minimize gastrointestinal intolerance. 3

Adverse Effects

• Most common adverse effects are gastrointestinal: diarrhea (7.2-10.7%), nausea, and vomiting. 1, 4
• The 14:1 ratio high-dose formulation (90/6.4 mg/kg/day) causes less diarrhea than other amoxicillin-clavulanate preparations while maintaining efficacy. 4
• Rash, urticaria, and hypersensitivity reactions may occur. 1

Pharmacokinetic Rationale for High-Dose Therapy

• High-dose amoxicillin (90 mg/kg/day) maintains serum concentrations above the MIC for ≥34% of the dosing interval, which is necessary for efficacy against penicillin-resistant S. pneumoniae (MICs 2-4 mg/L). 7
• The high-dose regimen achieved clinical response rates of 76-95% and eradicated penicillin-resistant S. pneumoniae in clinical trials. 4, 5
• Standard doses (45 mg/kg/day) are fully effective only against strains with amoxicillin MICs ≤2 mg/L. 7