What are the recommended treatment guidelines for community-acquired pneumonia?

Community-Acquired Pneumonia Treatment Guidelines

The recommended first-line treatment for community-acquired pneumonia (CAP) is a β-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus either azithromycin or a respiratory fluoroquinolone, with specific regimens based on severity and risk factors for resistant pathogens. 1, 2

Outpatient Treatment

For previously healthy patients with no risk factors for drug-resistant Streptococcus pneumoniae (DRSP):

• First choice: Macrolide (azithromycin 500 mg on day 1, then 250 mg daily for days 2-5) 3
• Alternative: Doxycycline (comparable efficacy to macrolides or fluoroquinolones in mild-to-moderate CAP) 2, 4

For patients with comorbidities or risk factors for DRSP:

• First choice: Respiratory fluoroquinolone (levofloxacin 750 mg daily) 5
• Alternative: β-lactam plus macrolide (amoxicillin or amoxicillin-clavulanate plus azithromycin) 2

Inpatient Non-ICU Treatment

• Standard regimen: β-lactam (ceftriaxone, cefotaxime, ampicillin-sulbactam) plus azithromycin (strong recommendation, level II evidence) 1
• Alternative: Respiratory fluoroquinolone monotherapy (strong recommendation, level I evidence) 1
• For penicillin-allergic patients: Respiratory fluoroquinolone plus aztreonam 1

Inpatient ICU Treatment

• Standard regimen: β-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus either azithromycin or a respiratory fluoroquinolone 1

For patients with Pseudomonas risk factors:

• Preferred regimen: Antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either:
  • Ciprofloxacin or levofloxacin (750 mg), OR
  • Aminoglycoside plus azithromycin, OR
  • Aminoglycoside plus antipneumococcal fluoroquinolone 1, 2

For suspected MRSA:

• Add vancomycin or linezolid to standard regimen 1

Duration of Therapy

• Minimum duration: 5 days (moderate recommendation, level I evidence) 1, 2
• Criteria for discontinuation: Patient should be afebrile for 48-72 hours and have no more than one CAP-associated sign of clinical instability 1
• Biomarkers, particularly procalcitonin, may guide shorter treatment duration 2

Switching from IV to Oral Therapy

• Switch when patient is:
  • Hemodynamically stable
  • Clinically improving
  • Able to ingest medications
  • Has normally functioning gastrointestinal tract 1
• Inpatient observation while receiving oral therapy is not necessary 1

Special Considerations

Atypical Pathogens

• Macrolides or doxycycline provide coverage for atypical pathogens (Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella) 2, 6
• Azithromycin has shown efficacy against macrolide-resistant pneumococcal strains in clinical practice despite in vitro resistance (in vivo-in vitro paradox) 7

Adjunctive Therapies

• Consider drotrecogin alfa activated within 24 hours of admission for persistent septic shock despite adequate fluid resuscitation 1
• Screen for occult adrenal insufficiency in hypotensive, fluid-resuscitated patients 1
• Consider non-invasive ventilation for respiratory distress, particularly in patients with COPD 2

Practical Considerations

• The first antibiotic dose should be administered while still in the emergency department 1
• Once a pathogen is identified, therapy should be narrowed to target that specific organism 1
• Early mobilization is recommended for all patients 2
• Consider thromboprophylaxis with low molecular weight heparin for patients with acute respiratory failure 2

Antibiotic Stewardship

• Use the narrowest spectrum antibiotics appropriate for the clinical situation
• Limit treatment duration to 5-7 days for most cases
• Implement systematic approaches to guide appropriate prescribing practices 2

Follow-up

• Clinical review for all patients at around 6 weeks
• Chest radiograph need not be repeated prior to hospital discharge if clinical recovery is satisfactory 2