Treatment of Community-Acquired Pneumonia in Healthy Adults
For healthy outpatient adults with community-acquired pneumonia (CAP), amoxicillin 1 g three times daily is the recommended first-line treatment. 1
Outpatient Treatment Options
First-line options for healthy adults without comorbidities:
- Amoxicillin 1 g three times daily (strong recommendation, moderate quality of evidence) 1
- Doxycycline 100 mg twice daily (conditional recommendation, low quality of evidence) 1
- Macrolide (azithromycin 500 mg on first day then 250 mg daily or clarithromycin 500 mg twice daily) only in areas with pneumococcal resistance to macrolides <25% (conditional recommendation, moderate quality of evidence) 1
For outpatients with comorbidities (chronic heart, lung, liver, or renal disease; diabetes; alcoholism; malignancy; or asplenia):
Combination therapy options:
- Amoxicillin/clavulanate (500 mg/125 mg three times daily, 875 mg/125 mg twice daily, or 2,000 mg/125 mg twice daily) OR a cephalosporin (cefpodoxime 200 mg twice daily or cefuroxime 500 mg twice daily) 1
- PLUS a macrolide (azithromycin 500 mg on first day then 250 mg daily, clarithromycin 500 mg twice daily) or doxycycline 100 mg twice daily 1
Monotherapy option:
- Respiratory fluoroquinolone (levofloxacin 750 mg daily, moxifloxacin 400 mg daily, or gemifloxacin 320 mg daily) 1
Inpatient Treatment (Non-ICU)
For patients requiring hospitalization but not intensive care:
- Combination therapy with a β-lactam (ampicillin + sulbactam 1.5-3 g every 6 h, cefotaxime 1-2 g every 8 h, ceftriaxone 1-2 g daily, or ceftaroline 600 mg every 12 h) and a macrolide (azithromycin 500 mg daily or clarithromycin 500 mg twice daily) 1, 2
- OR monotherapy with a respiratory fluoroquinolone (levofloxacin 750 mg daily, moxifloxacin 400 mg daily) 1, 2
Inpatient Treatment (ICU)
For severe CAP requiring ICU admission:
- A β-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus either azithromycin or a respiratory fluoroquinolone 1, 2
- For patients with risk factors for Pseudomonas infection: an antipneumococcal, antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either ciprofloxacin/levofloxacin or an aminoglycoside plus azithromycin 1, 2
Duration of Therapy
- Minimum of 5 days for all patients with CAP 2, 3
- Patients should be afebrile for 48-72 hours and have no more than 1 CAP-associated sign of clinical instability before discontinuation of therapy 2
- Longer duration may be needed if initial therapy was not active against the identified pathogen or if complicated by extrapulmonary infection 2
Special Considerations
Recent antibiotic exposure:
- If patient has had recent exposure to one class of antibiotics, treatment should be with antibiotics from a different class due to increased risk for bacterial resistance 1
Switching from IV to oral therapy:
- Patients should be switched from intravenous to oral therapy when they are hemodynamically stable, improving clinically, able to ingest medications, and have a normally functioning gastrointestinal tract 1, 2
Timing of first dose:
- For patients admitted through the emergency department, the first antibiotic dose should be administered while still in the ED 1, 2
Common Pitfalls and Caveats
- Macrolide monotherapy should only be used in areas with low pneumococcal resistance rates (<25%) 1
- Fluoroquinolones are associated with a higher rate of adverse events compared to macrolides, though they have lower rates of treatment failure 4
- Combination therapy with β-lactam/macrolide in the inpatient setting is associated with longer hospital stays and greater costs compared to fluoroquinolone monotherapy 4
- For patients with risk factors for methicillin-resistant Staphylococcus aureus (MRSA), consider adding vancomycin or linezolid to the treatment regimen 1, 2
- Always test for COVID-19 and influenza during respective seasons as their diagnosis may affect treatment and infection prevention strategies 3