Community-Acquired Pneumonia
ICD-10 J18.9 · ICD-11 CA40.Z

Treatment of Community-Acquired Pneumonia in Otherwise Healthy Outpatient Adults Without Comorbidities

Clinical Scenario

This protocol applies to adults aged 18 years or older presenting with community-acquired pneumonia who are being managed in the outpatient setting. The defining feature of this population is the absence of significant comorbidities — specifically no chronic heart, lung, liver, or renal disease, no diabetes mellitus, no alcoholism, no malignancy, and no asplenia.

Additionally, these patients have no risk factors for antibiotic-resistant pathogens: no prior respiratory isolation of MRSA or Pseudomonas aeruginosa, and no recent hospitalisation with receipt of parenteral antibiotics in the last 90 days.

Treatment Approach

For this low-risk outpatient population, the recommended approach involves a short course of oral antibiotic monotherapy. The guideline identifies several antibiotic classes — including a penicillin-class agent, a tetracycline-class agent, and macrolides (conditionally, depending on local resistance patterns) — as appropriate options.

The specific antibiotic, dose, and minimum treatment duration are defined in the full evidence-based protocol, along with the recommendation strength and evidence quality for each option.

Full regimen details available in the structured protocol →
Treatment Goals

The endpoint guiding antibiotic duration is clinical stability, defined as:

Most patients reach clinical stability within the first 48 to 72 hours. Antibiotic therapy should continue until stability is achieved, and for no fewer than 5 days total.

Instant Access to Structured Evidence-Based Regimens

References

  1. For healthy outpatient adults without comorbidities listed below or risk factors for antibiotic resistant pathogens, we recommend (Table 3):
  2. Risk factors include prior respiratory isolation of MRSA or P. aeruginosa or recent hospitalization AND receipt of parenteral antibiotics (in the last 90 d).
  3. amoxicillin 1 g three times daily (strong recommendation, moderate quality of evidence), or doxycycline 100 mg twice daily (conditional recommendation, low quality of evidence), or a 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 of evidence).
  4. We recommend that the duration of antibiotic therapy should be guided by a validated measure of clinical stability (resolution of vital sign abnormalities [heart rate, respiratory rate, blood pressure, oxygen saturation, and temperature], ability to eat, and normal mentation), and antibiotic therapy should be continued until the patient achieves stability and for no less than a total of 5 days (strong recommendation, moderate quality of evidence).
  5. As most patients will achieve clinical stability within the first 48 to 72 hours, a total duration of therapy of 5 days will be appropriate for most patients.
DOI: 10.1164/rccm.201908-1581ST View source ↗