What are the guidelines for using Augmentin (amoxicillin-clavulanate), cefuroxime, levofloxacin, doxycycline (doxy), azithromycin (azithro), and faropenem in treating pneumonia?

Antibiotic Selection in Pneumonia: Evidence-Based Approach

Community-Acquired Pneumonia (CAP)

Hospitalized Patients (Non-ICU)

For hospitalized patients with moderate-severity CAP, use combination therapy with a β-lactam plus macrolide OR respiratory fluoroquinolone monotherapy. 1

Preferred regimens include:

• Cefuroxime (2g IV q8h) or ceftriaxone/cefotaxime PLUS azithromycin or clarithromycin 1
• Augmentin (amoxicillin-clavulanate) PLUS macrolide as an alternative β-lactam option 1
• Levofloxacin (750mg IV/PO daily) OR moxifloxacin as monotherapy 1

The combination approach provides coverage for both typical bacteria (S. pneumoniae, H. influenzae) and atypical pathogens (Mycoplasma, Chlamydophila, Legionella). 1 Recent evidence shows no mortality difference between amoxicillin and co-amoxiclav for CAP treatment, suggesting narrow-spectrum options may be adequate when appropriate. 2

Severe CAP (ICU Patients)

For severe pneumonia requiring ICU admission, use a β-lactam PLUS either a macrolide OR respiratory fluoroquinolone. 1, 3

Recommended combinations:

• Ceftriaxone or cefotaxime PLUS azithromycin 1
• Ceftriaxone or cefotaxime PLUS levofloxacin (750mg daily) 1
• Augmentin PLUS macrolide for patients with β-lactam allergies to cephalosporins 1

If Pseudomonas aeruginosa risk factors present (structural lung disease, recent broad-spectrum antibiotics, bronchiectasis):

• Antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, or meropenem) PLUS ciprofloxacin OR macrolide plus aminoglycoside 1, 3

Outpatient CAP

For outpatient treatment, use macrolide monotherapy (azithromycin) OR doxycycline in previously healthy patients without recent antibiotic exposure. 1, 4

For patients with comorbidities or recent antibiotic use:

• Respiratory fluoroquinolone (levofloxacin or moxifloxacin) monotherapy 1, 5
• β-lactam (amoxicillin or Augmentin) PLUS macrolide 1, 5

Azithromycin is FDA-approved for community-acquired pneumonia caused by C. pneumoniae, H. influenzae, M. pneumoniae, or S. pneumoniae in patients appropriate for oral therapy. 4

Hospital-Acquired Pneumonia (HAP)

Low Mortality Risk, No MRSA Factors

Use monotherapy with piperacillin-tazobactam (4.5g IV q6h), cefepime (2g IV q8h), levofloxacin (750mg IV daily), imipenem, or meropenem. 1, 3

Levofloxacin provides excellent coverage for typical HAP pathogens including MSSA and gram-negative organisms. 1

MRSA Risk Factors Present

Add vancomycin (15mg/kg IV q8-12h, target trough 15-20 mg/mL) OR linezolid (600mg IV q12h) to the above regimens. 1, 3

MRSA risk factors include: IV antibiotics within 90 days, hospitalization in units with >20% MRSA prevalence among S. aureus isolates, or prior MRSA colonization. 1, 3

High Mortality Risk or Recent Antibiotic Use

Use dual gram-negative coverage: combine two agents from different classes (avoid two β-lactams). 1, 3

Example combinations:

• Piperacillin-tazobactam OR cefepime PLUS levofloxacin or ciprofloxacin 1
• Carbapenem PLUS aminoglycoside (gentamicin 5-7mg/kg IV daily) 1
• PLUS vancomycin or linezolid for MRSA coverage 1, 3

Pathogen-Specific Therapy

Once a specific pathogen is identified, narrow therapy accordingly: 1

• S. pneumoniae (penicillin-susceptible): Penicillin G, amoxicillin, or ceftriaxone 1
• S. pneumoniae (penicillin-resistant, MIC ≤4): High-dose amoxicillin (3g/day), ceftriaxone, or respiratory fluoroquinolone 1
• H. influenzae (β-lactamase negative): Amoxicillin 1
• H. influenzae (β-lactamase positive): Augmentin, cefuroxime, or fluoroquinolone 1
• Atypical pathogens (Mycoplasma, Chlamydophila): Macrolide, doxycycline, or fluoroquinolone 1
• Legionella: Levofloxacin or azithromycin (levofloxacin preferred for severe cases) 1

Critical Management Principles

Duration of Therapy

Treat for 5-8 days in responding patients; biomarkers like procalcitonin can guide shorter durations. 1

Extend to 14-21 days only for Legionella, S. aureus, or gram-negative enteric bacilli. 1

IV to Oral Switch

Switch to oral therapy when clinically stable: temperature ≤37.8°C, heart rate ≤100/min, respiratory rate ≤24/min, systolic BP ≥90 mmHg, O₂ saturation ≥90%, normal mental status. 1, 3

This approach is safe even in severe pneumonia and facilitates early discharge without increased complications. 1, 6

COVID-19 Considerations

In confirmed COVID-19 pneumonia without bacterial co-infection evidence, empirical antibiotics are not routinely required. 1

However, if bacterial co-infection is suspected based on clinical deterioration, procalcitonin elevation, or positive cultures, use standard CAP regimens. 1 The relevant bacterial pathogens remain the same (S. pneumoniae, H. influenzae, S. aureus). 1

Common Pitfalls to Avoid

Do not use ciprofloxacin alone for pneumococcal pneumonia - it has inferior activity compared to levofloxacin or moxifloxacin. 1

Do not use monotherapy for Pseudomonas - always use combination therapy to prevent resistance development. 1, 3

Do not continue broad-spectrum antibiotics beyond 48 hours if cultures are negative and the patient is improving clinically. 1

Avoid prolonged IV therapy - switch to oral when stable to reduce complications and costs. 1, 6

Faropenem is not included in major guidelines for pneumonia treatment and lacks robust evidence for this indication compared to established agents. 1