Treatment Regimen for Community-Acquired Pneumonia
For patients with community-acquired pneumonia (CAP), treatment should be stratified based on patient characteristics, with amoxicillin as first-line therapy for healthy outpatients, combination therapy or respiratory fluoroquinolones for those with comorbidities, and β-lactam plus macrolide or respiratory fluoroquinolone for hospitalized patients. 1
Outpatient Treatment
Healthy Adults Without Comorbidities
- Amoxicillin 1 g three times daily (strong recommendation, moderate quality evidence) 2
- Doxycycline 100 mg twice daily (conditional recommendation, low quality evidence) 2, 1
- Macrolide (azithromycin 500 mg on first day then 250 mg daily or clarithromycin 500 mg twice daily or clarithromycin extended release 1,000 mg daily) only in areas with pneumococcal resistance to macrolides <25% (conditional recommendation, moderate quality evidence) 2
Adults With Comorbidities
Comorbidities include chronic heart, lung, liver, or renal disease; diabetes mellitus; alcoholism; malignancy; or asplenia.
Combination therapy options:
- 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 a cephalosporin (cefpodoxime 200 mg twice daily or cefuroxime 500 mg twice daily) 2
- PLUS a macrolide (azithromycin 500 mg on first day then 250 mg daily, clarithromycin 500 mg twice daily or extended release 1,000 mg once daily) (strong recommendation, moderate quality evidence) 2, 3
- OR doxycycline 100 mg twice daily (conditional recommendation, low quality evidence) 2
Monotherapy option:
Hospitalized Patients
Non-Severe CAP
- Combined therapy with a β-lactam (ampicillin, ceftriaxone) plus a macrolide (azithromycin, clarithromycin) 1, 3
- When oral treatment is contraindicated, use intravenous ampicillin or benzylpenicillin together with erythromycin or clarithromycin 2
- For patients intolerant to β-lactams or macrolides, a respiratory fluoroquinolone with enhanced activity against S. pneumoniae (such as levofloxacin) is an alternative 2, 4
Severe CAP
- Intravenous combination of a broad-spectrum β-lactamase stable antibiotic (co-amoxiclav, cefuroxime, cefotaxime, or ceftriaxone) together with a macrolide (clarithromycin or erythromycin) 2, 3
- For patients intolerant to β-lactams or macrolides, a fluoroquinolone with enhanced activity against S. pneumoniae (such as levofloxacin) together with intravenous benzylpenicillin 2
Treatment Duration
- For non-severe CAP: 5-7 days is typically sufficient 5, 6
- For severe CAP without identified pathogens: 10 days 3
- For specific pathogens like Legionella, staphylococcal, or Gram-negative enteric bacilli: 14-21 days 2
Special Considerations
Recent Antibiotic Exposure
- Patients with recent exposure to one class of antibiotics should receive treatment from a different class due to increased risk of bacterial resistance 1, 3
Treatment Failure
- For patients not improving on initial therapy:
Common Pitfalls to Avoid
- Underestimating severity of pneumonia, which can lead to inappropriate treatment intensity 1, 3
- Using macrolide monotherapy in areas with high pneumococcal resistance (≥25%) 2, 1
- Failing to consider resistant pathogens in patients with risk factors 1
- Delaying antibiotic therapy in severe cases, which increases mortality 2
- Transferring patients to ICU after initial ward admission rather than direct ICU admission, which is associated with higher mortality 2
Short-course antibiotic regimens (≤7 days) have been shown to be as effective as longer courses for mild to moderate CAP, which may help limit antimicrobial resistance, decrease cost, and improve patient adherence 6.