What is the recommended outpatient treatment for pneumonia?

Outpatient Treatment for Community-Acquired Pneumonia

For healthy adults without comorbidities, amoxicillin 1 g three times daily is the first-line treatment for outpatient community-acquired pneumonia. 1

Treatment Algorithm Based on Patient Characteristics

Healthy Adults Without Comorbidities

1. First-line therapy (in order of preference):
   • Amoxicillin 1 g three times daily for 5 days (strong recommendation, moderate quality evidence) 2, 1
   • Doxycycline 100 mg twice daily for 5 days (conditional recommendation, low quality evidence) 2, 1
   • Macrolide (azithromycin 500 mg on first day, then 250 mg daily for 4 days) ONLY in areas with pneumococcal resistance to macrolides <25% (conditional recommendation, moderate quality evidence) 2, 1

Adults With Comorbidities

Comorbidities include: chronic heart, lung, liver, or renal disease; diabetes mellitus; alcoholism; malignancy; or asplenia 2, 1

1. 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) PLUS
   • A macrolide (azithromycin 500 mg on first day then 250 mg daily, OR clarithromycin 500 mg twice daily) OR doxycycline 100 mg twice daily 2

2. Monotherapy option:

   • Respiratory fluoroquinolone (levofloxacin 750 mg daily, moxifloxacin 400 mg daily, or gemifloxacin 320 mg daily) 2, 1

Treatment Duration

• Minimum duration for most patients: 5 days 1
• Patient should be afebrile for 48-72 hours and have no more than one CAP-associated sign of clinical instability before discontinuing therapy 1
• For atypical pneumonia (especially Legionella), extend treatment to 7-14 days 1

Monitoring and Follow-up

• Assess response at 48-72 hours after initiating therapy 1
• Clinical improvement typically includes reduction in fever, improvement in respiratory symptoms, and stabilization of vital signs 1
• If no improvement after 48-72 hours, reassess diagnosis and consider alternative antimicrobial therapy 1

Special Considerations

Elderly Patients in Long-term Care Facilities

• Consider combination of amoxicillin-clavulanate and doxycycline for broader coverage 1
• Shorter courses may be inadequate due to comorbidities, altered immune response, and increased risk of drug-resistant pathogens 1

Recent Antibiotic Exposure

• Use antibiotics from a different class due to increased risk of bacterial resistance 1

Common Pitfalls and Caveats

1. Macrolide resistance: Macrolide monotherapy should only be used in areas where pneumococcal resistance is <25% 2, 1

2. Inappropriate use of oral therapy: Azithromycin should not be used in patients with pneumonia who are inappropriate for oral therapy due to:

   • Moderate to severe illness
   • Cystic fibrosis
   • Nosocomially acquired infections
   • Known or suspected bacteremia
   • Need for hospitalization
   • Elderly or debilitated status
   • Significant underlying health problems 3

3. Overuse of broad-spectrum antibiotics: Despite guidelines, broad-spectrum antibiotics are often prescribed for otherwise healthy patients when narrow-spectrum would be appropriate 4

4. Treatment duration: Although 5-day courses are recommended, 10-day durations are still commonly prescribed in practice 4

5. QT prolongation risk: Azithromycin can cause QT prolongation, particularly in patients with cardiac risk factors 3

6. C. difficile risk: Consider the risk of Clostridium difficile-associated diarrhea with all antibiotics 3

The evidence strongly supports using the narrowest spectrum antibiotic that will effectively treat the likely pathogens, with treatment duration of 5 days for most patients with uncomplicated community-acquired pneumonia.