What is the recommended dosage of amoxicillin (amoxicillin) for pediatric patients with Community-Acquired Pneumonia (CAP)?

Amoxicillin Dosing for Pediatric Community-Acquired Pneumonia

Recommended Dosage

The definitive first-line treatment for pediatric community-acquired pneumonia is amoxicillin 90 mg/kg/day divided into 2 doses (maximum 4 g/day), which provides superior coverage against resistant Streptococcus pneumoniae. 1, 2, 3

Outpatient Management

• Children over 3 months of age should receive amoxicillin 90 mg/kg/day divided into 2 doses for community-acquired pneumonia 2, 3
• The maximum daily dose is 4 g/day for severe infections or in areas with high pneumococcal resistance 2
• Treatment duration should be 10 days for pneumonia 2

Critical Dosing Considerations

• Underdosing with 40-45 mg/kg/day instead of the recommended 90 mg/kg/day is a common and dangerous error that fails to overcome pneumococcal resistance 3
• The higher dose (90 mg/kg/day) is essential to achieve adequate drug concentrations at the infection site against potentially resistant organisms 3
• Lower doses of 45 mg/kg/day divided every 12 hours are only appropriate for mild to moderate respiratory tract infections, not pneumonia 2

Treatment Duration Evidence

• A 5-day course of high-dose amoxicillin (80-90 mg/kg/day) is non-inferior to 10 days for uncomplicated CAP in children aged 6-59 months 4, 5
• Recent high-quality evidence from the CAP-IT trial demonstrated that 3-day treatment was non-inferior to 7-day treatment, though cough duration was slightly longer (12 vs 10 days) with the shorter course 6, 7
• Despite evidence supporting shorter courses, current guidelines recommend 10 days of treatment to ensure adequate eradication and minimize treatment failure 2

Practical Algorithm for Duration

• Standard uncomplicated CAP: 10 days of treatment 2
• Uncomplicated CAP with good clinical response: Consider 5-7 days based on recent evidence 6, 4, 5
• Complicated pneumonia (empyema, abscess, necrotizing infiltrates): Longer courses beyond 10 days may be needed 1

Age-Specific Considerations

• Children under 5 years: Amoxicillin 90 mg/kg/day in 2 doses is the first-line treatment, as atypical pathogens are uncommon in this age group 3
• Children 5 years and older: Amoxicillin 90 mg/kg/day in 2 doses remains first-line, but consider adding azithromycin (10 mg/kg day 1, then 5 mg/kg days 2-5) if atypical pathogens (Mycoplasma, Chlamydophila) are suspected based on clinical presentation 1, 3

Alternative Regimens

For Incomplete Immunization or β-lactamase Producing Organisms

• Amoxicillin-clavulanate (amoxicillin component 90 mg/kg/day in 2 doses) should be used for children not fully immunized against Haemophilus influenzae type b or Streptococcus pneumoniae 1, 3
• This provides coverage for β-lactamase-producing H. influenzae 3

For Suspected Staphylococcus aureus

• Amoxicillin-clavulanate (amoxicillin component 90 mg/kg/day in 2 doses) for outpatient treatment of suspected MSSA 3
• Add clindamycin (30-40 mg/kg/day in 3-4 doses) to beta-lactam therapy if MRSA is suspected (severe presentation, necrotizing infiltrates, empyema, recent influenza) 1, 3

Reassessment and Treatment Failure

• All patients should be reassessed at 48-72 hours for clinical improvement 2, 3
• Lack of improvement requires reevaluation for complications (empyema, abscess), alternative diagnoses, or resistant organisms 2, 3
• Consider hospitalization for intravenous therapy if outpatient treatment fails 3

Common Pitfalls to Avoid

• Do not use lower doses (40-45 mg/kg/day) for pneumonia—this is inadequate for resistant pneumococci 3
• Do not use macrolides as first-line monotherapy for presumed bacterial pneumonia in children under 5 years 3
• Do not fail to consider MRSA in patients with severe pneumonia, especially with necrotizing infiltrates, empyema, or recent influenza infection 3
• Do not use cefixime for pediatric pneumonia—it is explicitly not recommended 3