What is the recommended oral Augmentin (amoxicillin/clavulanate) dose for a child with a lower respiratory tract infection, based on weight, and how should it be adjusted for renal impairment or a penicillin allergy?

Augmentin Dosing for Pediatric Lower Respiratory Tract Infections

For pediatric lower respiratory tract infections, use Augmentin 90 mg/kg/day of the amoxicillin component divided into 2 doses (maximum 4 g/day), given for 10 days. 1, 2

Weight-Based Dosing Algorithm

Standard High-Dose Regimen (Preferred for LRTI)

• Calculate 90 mg/kg/day of amoxicillin component, divided into 2 doses (every 12 hours) 1, 2
• Use the 600 mg/42.9 mg per 5 mL suspension (14:1 ratio) to achieve this dosing 2
• Maximum total daily dose: 4,000 mg amoxicillin per day 1
• Maximum single dose: 2,000 mg per dose 2

Age and Weight Restrictions

• Minimum age: 3 months – do not use Augmentin in infants younger than 3 months for oral therapy 2, 3
• For infants under 3 months with serious bacterial infection, use IV ampicillin + gentamicin instead 2
• Children ≥40 kg: dose as adults (875/125 mg twice daily for respiratory infections) 1, 3

Practical Dosing Examples

Example Calculations by Weight

• 10 kg child: 90 mg/kg/day = 900 mg/day ÷ 2 = 450 mg per dose (7.5 mL of 600/42.9 suspension twice daily) 1
• 20 kg child: 90 mg/kg/day = 1,800 mg/day ÷ 2 = 900 mg per dose (15 mL of 600/42.9 suspension twice daily) 1
• 30 kg child: 90 mg/kg/day = 2,700 mg/day ÷ 2 = 1,350 mg per dose (22.5 mL of 600/42.9 suspension twice daily) 1

Rationale for High-Dose Regimen in LRTI

Why 90 mg/kg/day is Standard for LRTI

• Provides adequate coverage for penicillin-resistant Streptococcus pneumoniae (MIC up to 2-4 mg/L) 2, 4, 5
• Covers β-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis, the most common LRTI pathogens 1, 2, 4
• The 14:1 amoxicillin-to-clavulanate ratio (90/6.4 mg/kg/day) causes less diarrhea than older 7:1 formulations while maintaining efficacy 2, 5

Specific LRTI Indications for High-Dose

• Community-acquired pneumonia in children <5 years: 90 mg/kg/day in 2 doses 1, 2
• Community-acquired pneumonia in children ≥5 years: 90 mg/kg/day in 2 doses 1, 2
• Incomplete H. influenzae type b vaccination: use Augmentin instead of amoxicillin alone at 90 mg/kg/day 1, 2
• Concurrent purulent acute otitis media with pneumonia: 90 mg/kg/day 1, 2

Treatment Duration and Monitoring

Standard Duration

• 10 days for bacterial pneumonia and LRTI 1, 2
• Do not shorten course even if symptoms improve earlier 1

Expected Clinical Response

• Clinical improvement should occur within 48-72 hours (fever reduction, decreased respiratory distress, improved appetite) 1, 2
• Fever typically resolves within 24-48 hours for pneumococcal pneumonia, though cough may persist longer 1
• If no improvement or worsening after 48-72 hours: consider atypical pathogens (Mycoplasma, Chlamydia) and add a macrolide, or reassess diagnosis 1, 2

Renal Impairment Adjustments

Dosing Modifications by GFR

• GFR 10-30 mL/min: reduce to 500/125 mg or 250/125 mg every 12 hours (depending on severity) 3
• GFR <10 mL/min: reduce to 500/125 mg or 250/125 mg every 24 hours 3
• Hemodialysis patients: 500/125 mg or 250/125 mg every 24 hours, with additional dose during and after dialysis 3
• Do not use 875/125 mg dose if GFR <30 mL/min 3

Penicillin Allergy Alternatives

Non-Anaphylactic (Type IV) Reactions

• Second- or third-generation cephalosporins (cefdinir 14 mg/kg/day in 1-2 doses, or cefuroxime 30 mg/kg/day in 2 doses) 1
• Cross-reactivity risk with cephalosporins is <3% for non-IgE-mediated reactions 1

Type I (IgE-Mediated) Anaphylactic Reactions

• Levofloxacin 16-20 mg/kg/day in 1-2 doses (maximum 750 mg/day) for children ≥6 months 1
• Clindamycin 30-40 mg/kg/day in 3-4 doses (covers S. pneumoniae but not H. influenzae) 1
• Azithromycin 10 mg/kg day 1, then 5 mg/kg days 2-5 (inferior efficacy for resistant S. pneumoniae) 1

Critical Pitfalls to Avoid

Common Dosing Errors

• Do NOT use 45 mg/kg/day for LRTI – this lower dose is only for mild infections like uncomplicated sinusitis; LRTI requires 90 mg/kg/day 1, 2
• Do NOT substitute two 250/125 mg tablets for one 500/125 mg tablet – they contain different clavulanate amounts and are not equivalent 3
• Do NOT use 250/125 mg tablets in children <40 kg – the amoxicillin-to-clavulanate ratio is inappropriate for pediatric dosing 3
• Do NOT use the 125/31 or 250/62.5 suspensions for high-dose therapy – you must use the 600/42.9 suspension to achieve 90 mg/kg/day without excessive volume 2

Formulation Selection Errors

• Verify suspension concentration before dispensing – the 600 mg/5 mL (ES-600) formulation is specifically designed for high-dose pediatric therapy 2
• The older 400/57 mg per 5 mL suspension can be used but requires larger volumes and has a less favorable clavulanate ratio 2, 3

Clinical Management Errors

• Do NOT prescribe Augmentin for viral LRTI – most bronchiolitis and many pneumonias in young children are viral 6
• Do NOT continue therapy beyond 48-72 hours without improvement – lack of response suggests atypical pathogens, viral infection, or complications requiring reevaluation 1, 2
• Do NOT use Augmentin as monotherapy for atypical pneumonia in children >5 years – add a macrolide if Mycoplasma or Chlamydia is suspected 1