What alternative antibiotics can be used to treat community‑acquired pneumonia in a baby (neonate or infant) when penicillin cannot be used, such as due to allergy, treatment failure, or concurrent calcium‑containing fluids?

Alternative Antibiotics for Community-Acquired Pneumonia in Infants

For infants with community-acquired pneumonia who cannot receive penicillin-based antibiotics, azithromycin (10 mg/kg on day 1, then 5 mg/kg daily on days 2–5) is the preferred oral alternative, while ceftriaxone (50–100 mg/kg/day IV) or cefotaxime (150 mg/kg/day IV every 8 hours) are the definitive intravenous alternatives. 1

Outpatient Oral Alternatives

First-Line Non-Penicillin Option: Azithromycin

• Azithromycin provides excellent coverage for Streptococcus pneumoniae, Mycoplasma pneumoniae, and Chlamydophila pneumoniae in penicillin-allergic infants. 2
• Dosing: 10 mg/kg as a single dose on day 1 (maximum 500 mg), followed by 5 mg/kg once daily on days 2–5 (maximum 250 mg/day). 1, 3
• This regimen avoids all beta-lactam exposure and is appropriate for mild-to-moderate pneumonia when oral therapy is feasible. 1

Second-Line Oral Options for Non-Severe Allergy

• For non-anaphylactic penicillin reactions, oral cephalosporins (cefpodoxime, cefprozil, or cefuroxime) may be used under medical supervision because cross-reactivity risk is low (1–3%). 1
• These agents provide adequate coverage for S. pneumoniae and Haemophilus influenzae. 1

Severe Allergy: Levofloxacin

• For severe (anaphylactic) penicillin allergy in infants ≥6 months, levofloxacin is the preferred alternative: 16–20 mg/kg/day divided every 12 hours (maximum 750 mg/day). 1, 2
• Fluoroquinolones have excellent antipneumococcal activity but should be reserved for cases where beta-lactams and macrolides are contraindicated. 2

Inpatient Parenteral Alternatives

Definitive First-Line IV Regimen

• Ceftriaxone (50–100 mg/kg/day IV every 12–24 hours) or cefotaxime (150 mg/kg/day IV every 8 hours) provides reliable coverage of penicillin-resistant S. pneumoniae, beta-lactamase-producing H. influenzae, and Klebsiella pneumoniae. 1
• These third-generation cephalosporins are the definitive choice when comprehensive coverage is required and ampicillin cannot be used. 1

When to Add MRSA Coverage

• Add vancomycin (40–60 mg/kg/day IV every 6–8 hours) or clindamycin (40 mg/kg/day IV every 6 hours) to the cephalosporin regimen if severe pneumonia with necrotizing infiltrates, empyema, or recent influenza infection raises concern for MRSA. 1, 2

Alternative IV Macrolide

• Azithromycin IV (10 mg/kg on days 1 and 2, then transition to oral) is an option for hospitalized penicillin-allergic infants, particularly when atypical pathogens are suspected. 1, 2

Special Considerations for Neonates (<3 Months)

Empirical Regimen for Early-Onset Infection

• Ampicillin plus an aminoglycoside (gentamicin) is the standard first-line therapy for neonatal pneumonia to cover group B streptococci, Listeria monocytogenes, and Enterobacteriaceae. 4
• If ampicillin cannot be used due to allergy, substitute cefotaxime (150 mg/kg/day IV every 8 hours) plus an aminoglycoside for the first 2–3 days, then narrow based on culture results. 4

Late-Onset Nosocomial Infection

• Vancomycin plus ceftazidime (±aminoglycoside for the first 2–3 days) is recommended for late-onset infections in neonates, particularly those with central lines or prolonged ventilation. 4

Treatment Duration and Monitoring

• Complete a 7–10 day course for most pediatric pneumonia cases, with 10 days preferred for severe infections. 1, 5
• Clinical improvement (reduced fever, better respiratory effort, improved oral intake) should occur within 48–72 hours. 1
• If no improvement occurs within 48–72 hours, reassess for complications (empyema, necrotizing pneumonia), resistant organisms, or atypical pathogens and consider adding a macrolide or escalating to IV therapy. 1

Critical Pitfalls to Avoid

• Do not use ciprofloxacin because it lacks adequate pneumococcal coverage and is contraindicated for community-acquired pneumonia. 2
• Do not use cefdinir as initial empiric therapy because it lacks activity against penicillin-resistant S. pneumoniae and Staphylococcus aureus. 1
• Do not stop antibiotics early even if symptoms improve; complete the full course to prevent relapse. 2
• For infants <3 months with beta-lactam allergy, hospitalization is strongly preferable to initiate appropriate parenteral therapy under close monitoring. 1