What are the recommended antibiotics for a pediatric patient with community-acquired pneumonia, considering factors such as age, medical history, and severity of illness?

Recommended Antibiotics for Pediatric Community-Acquired Pneumonia

Amoxicillin 90 mg/kg/day divided into 2 doses is the definitive first-line antibiotic for outpatient treatment of pediatric community-acquired pneumonia in children over 3 months of age. 1, 2

Outpatient Treatment Algorithm

Children Under 5 Years Old

• First-line: Amoxicillin 90 mg/kg/day divided into 2 doses (maximum 4 g/day) 1, 2
• Duration: 5 days of therapy is recommended, with clinical reassessment at 48-72 hours 1, 3
• Alternative if not fully immunized: Amoxicillin-clavulanate (amoxicillin component 90 mg/kg/day in 2 doses) to cover β-lactamase-producing Haemophilus influenzae 1, 3
• Do NOT use macrolides as first-line therapy in this age group, as atypical pathogens (Mycoplasma pneumoniae, Chlamydophila pneumoniae) are uncommon under age 5 1

Children 5 Years and Older

• First-line: Amoxicillin 90 mg/kg/day in 2 doses (maximum 4 g/day) 1, 2
• Add azithromycin if atypical pathogens are suspected based on clinical presentation: 10 mg/kg on day 1, then 5 mg/kg/day on days 2-5 (maximum 500 mg day 1, then 250 mg days 2-5) 1, 2, 4
• Duration: 5 days for amoxicillin alone; azithromycin is a 5-day course 1, 3

Special Considerations for Outpatient Treatment

• If MRSA suspected: Add clindamycin 30-40 mg/kg/day in 3-4 doses to beta-lactam therapy 1, 2
• If Staphylococcus aureus (MSSA) suspected: Use amoxicillin-clavulanate (amoxicillin component 90 mg/kg/day in 2 doses) 1

Inpatient Treatment Algorithm

Fully Immunized, Low-Risk Children

• First-line: Ampicillin 150-200 mg/kg/day IV every 6 hours OR penicillin G 100,000-250,000 U/kg/day IV every 4-6 hours 1
• Alternative: Ceftriaxone 50-100 mg/kg/day IV every 12-24 hours 1

Not Fully Immunized or High-Risk Children

• First-line: Ceftriaxone 50-100 mg/kg/day IV every 12-24 hours OR cefotaxime 150 mg/kg/day IV every 8 hours 1
• Add vancomycin 40-60 mg/kg/day IV every 6-8 hours OR clindamycin 40 mg/kg/day IV every 6-8 hours if MRSA is suspected 1
• MRSA risk factors include: Severe presentation, necrotizing infiltrates, empyema, recent influenza infection, or failure to improve on standard therapy 1

Atypical Pneumonia (Hospitalized)

• Azithromycin IV 10 mg/kg on days 1 and 2, then transition to oral therapy 1, 4
• Alternative: Erythromycin lactobionate 20 mg/kg/day IV every 6 hours 1

Penicillin Allergy Management

Non-Severe Allergic Reactions

• Trial of oral cephalosporins under medical supervision: cefpodoxime, cefprozil, or cefuroxime 1, 2
• Cross-reactivity risk between penicillins and cephalosporins is low (approximately 1-3%) for non-anaphylactic reactions 1

Severe Allergic Reactions (Anaphylaxis)

• Levofloxacin: 16-20 mg/kg/day in 2 doses for children 6 months to 5 years, OR 8-10 mg/kg/day once daily for children 5-16 years (maximum 750 mg/day) 1
• Alternative: Linezolid based on age and severity 1

Critical Dosing Considerations

Common Pitfalls to Avoid

• Underdosing amoxicillin (using 40-45 mg/kg/day instead of 90 mg/kg/day) is a dangerous error that leads to treatment failure due to resistant pneumococci 1, 2, 5
• Inappropriate use of macrolides as first-line therapy for presumed bacterial pneumonia should be avoided; macrolides are reserved for atypical pneumonia or as add-on therapy in children ≥5 years 1, 2
• Failure to consider MRSA in patients with severe pneumonia, necrotizing infiltrates, empyema, or recent influenza is a significant concern 1

Treatment Monitoring

• Reassess all patients at 48-72 hours for clinical improvement 1, 2, 5
• If no improvement occurs: Consider complications (parapneumonic effusion, empyema), alternative diagnoses, or resistant organisms 1
• Obtain appropriate cultures before starting antibiotics in hospitalized patients 1
• Consider drainage for significant parapneumonic effusions 1

Evidence Quality Notes

The recommendation for 5-day amoxicillin therapy is supported by recent high-quality evidence showing non-inferiority compared to 7-10 day courses, with moderate certainty of evidence 3, 6, 7. The higher dose of 90 mg/kg/day is essential to overcome pneumococcal resistance and is strongly recommended by both the American Academy of Pediatrics and Infectious Diseases Society of America 1, 2, 5.