Recommended Antibiotics for Community-Acquired Pneumonia (CAP)
For community-acquired pneumonia, the recommended first-line treatment depends on patient setting and comorbidities, with amoxicillin recommended for healthy outpatients, combination therapy or respiratory fluoroquinolones for those with comorbidities, and β-lactam plus macrolide or respiratory fluoroquinolone for hospitalized patients. 1, 2
Outpatient Treatment
Healthy Adults Without Comorbidities
- Amoxicillin 1 g three times daily (strong recommendation, moderate quality evidence) 2, 1
- Doxycycline 100 mg twice daily (conditional recommendation, low quality evidence) 2, 1
- Macrolides (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 evidence) 2
Adults With Comorbidities (chronic heart, lung, liver, or renal disease; diabetes; alcoholism; malignancy; asplenia)
- Combination therapy:
- β-lactam (amoxicillin/clavulanate 500 mg/125 mg three times daily, or 875 mg/125 mg twice daily, or 2,000 mg/125 mg twice daily, or cefpodoxime 200 mg twice daily, or cefuroxime 500 mg twice daily) PLUS
- Macrolide (azithromycin 500 mg on first day then 250 mg daily, or clarithromycin 500 mg twice daily) 2, 3
- OR Monotherapy with a respiratory fluoroquinolone (levofloxacin 750 mg daily, moxifloxacin 400 mg daily, or gemifloxacin 320 mg daily) 2, 4
Inpatient Treatment (Non-ICU)
- 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) PLUS macrolide (azithromycin 500 mg daily or clarithromycin 500 mg twice daily) (strong recommendation, high quality evidence) 2, 5
- OR Monotherapy with a respiratory fluoroquinolone (levofloxacin 750 mg daily, moxifloxacin 400 mg daily) (strong recommendation, high quality evidence) 2, 4
- Alternative for patients with contraindications to both macrolides and fluoroquinolones: β-lactam (as above) PLUS doxycycline 100 mg twice daily (conditional recommendation, low quality evidence) 2
Severe CAP (ICU Patients)
- β-lactam PLUS macrolide (strong recommendation, moderate quality evidence) 2
- OR β-lactam PLUS respiratory fluoroquinolone (strong recommendation, low quality evidence) 2
Key Considerations
- Recent antibiotic exposure should guide therapy choice - patients with recent exposure to one class of antibiotics should receive treatment from a different class due to increased risk for bacterial resistance 2, 1
- Local resistance patterns should be considered when selecting therapy 1, 3
- Fluoroquinolones should be used judiciously due to potential adverse events and risk of promoting resistance 2, 4
- Studies show that β-lactam plus macrolide combination therapy is associated with lower mortality than β-lactam monotherapy in hospitalized patients 2
- A systematic review found that fluoroquinolone monotherapy resulted in fewer clinical failures and treatment discontinuations than β-lactam/macrolide combinations, though mortality rates were similar 2
Cost Considerations
- Doxycycline is significantly more cost-effective than levofloxacin ($64.98 vs. $122.07 per treatment course) with similar efficacy for hospitalized patients 6
- Empiric therapy with low-dose parenteral cefuroxime with or without erythromycin, followed by outpatient clarithromycin has been shown to be less costly than other common regimens 7
Treatment Duration
- For outpatients with CAP, a 5-day course of appropriate antibiotics is generally sufficient 2, 5
- For hospitalized patients with CAP, treatment duration typically ranges from 5-7 days, based on clinical response 2
Common Pitfalls to Avoid
- Using macrolide monotherapy in areas with pneumococcal resistance ≥25% 2, 1
- Underestimating severity of illness, which can lead to inappropriate treatment selection 1
- Failing to consider recent antibiotic exposure when selecting therapy 2
- Not adjusting therapy based on diagnostic testing results (e.g., pneumococcal and Legionella urinary antigens) 1