Red Flags
- Hypotension requiring vasopressors or respiratory failure requiring mechanical ventilation: direct ICU admission.[2]
First-line treatment
| Drug | Class | Adult | Paediatric | Notes |
|---|---|---|---|---|
| Amoxicillin-clavulanate or a cephalosporin PLUS a macrolide or doxycycline; OR a respiratory fluoroquinolone alone[2] | Adult outpatient regimen with comorbidities | Amoxicillin/clavulanate 500/125 mg three times daily or 875/125 mg twice daily or 2000/125 mg twice daily, or cefpodoxime 200 mg twice daily or cefuroxime 500 mg twice daily; PLUS azithromycin 500 mg day 1 then 250 mg daily, clarithromycin 500 mg twice daily (ER 1000 mg daily), or doxycycline 100 mg twice daily; OR levofloxacin 750 mg daily, moxifloxacin 400 mg daily, or gemifloxacin 320 mg daily. | — | Comorbidities: chronic heart, lung, liver or renal disease; diabetes; alcoholism; malignancy; asplenia. Table 3 gives combination therapy OR fluoroquinolone monotherapy without preference. Assess resistant-pathogen risks separately. |
| Amoxicillin or doxycycline (outpatient without listed comorbidities)[2] | Adult outpatient options | Amoxicillin 1 g three times daily OR doxycycline 100 mg twice daily. | — | For adults without comorbidities or resistant-pathogen risk factors. Macrolide monotherapy is another option only where pneumococcal macrolide resistance is <25%. |
| Beta-lactam plus macrolide OR respiratory fluoroquinolone alone (nonsevere inpatient)[2] | Adult inpatient options | Ceftriaxone 1–2 g daily plus azithromycin 500 mg daily; OR levofloxacin 750 mg daily or moxifloxacin 400 mg daily. | — | Without MRSA/Pseudomonas risk factors; examples shown, not an exhaustive list. Neither option is ranked above the other. |
| Beta-lactam plus macrolide OR beta-lactam plus respiratory fluoroquinolone (severe CAP)[2] | Adult severe-CAP options | Ceftriaxone 1–2 g daily plus azithromycin 500 mg daily; OR ceftriaxone 1–2 g daily plus levofloxacin 750 mg daily. | — | Without MRSA/Pseudomonas risk factors. For resistant-pathogen risks, apply Table 4 using local validation, cultures and reassessment. |
Amoxicillin-clavulanate or a cephalosporin PLUS a macrolide or doxycycline; OR a respiratory fluoroquinolone alone[2]
Adult outpatient regimen with comorbidities
- Adult
- Amoxicillin/clavulanate 500/125 mg three times daily or 875/125 mg twice daily or 2000/125 mg twice daily, or cefpodoxime 200 mg twice daily or cefuroxime 500 mg twice daily; PLUS azithromycin 500 mg day 1 then 250 mg daily, clarithromycin 500 mg twice daily (ER 1000 mg daily), or doxycycline 100 mg twice daily; OR levofloxacin 750 mg daily, moxifloxacin 400 mg daily, or gemifloxacin 320 mg daily.
- Paediatric
- —
Comorbidities: chronic heart, lung, liver or renal disease; diabetes; alcoholism; malignancy; asplenia. Table 3 gives combination therapy OR fluoroquinolone monotherapy without preference. Assess resistant-pathogen risks separately.
Amoxicillin or doxycycline (outpatient without listed comorbidities)[2]
Adult outpatient options
- Adult
- Amoxicillin 1 g three times daily OR doxycycline 100 mg twice daily.
- Paediatric
- —
For adults without comorbidities or resistant-pathogen risk factors. Macrolide monotherapy is another option only where pneumococcal macrolide resistance is <25%.
Beta-lactam plus macrolide OR respiratory fluoroquinolone alone (nonsevere inpatient)[2]
Adult inpatient options
- Adult
- Ceftriaxone 1–2 g daily plus azithromycin 500 mg daily; OR levofloxacin 750 mg daily or moxifloxacin 400 mg daily.
- Paediatric
- —
Without MRSA/Pseudomonas risk factors; examples shown, not an exhaustive list. Neither option is ranked above the other.
Beta-lactam plus macrolide OR beta-lactam plus respiratory fluoroquinolone (severe CAP)[2]
Adult severe-CAP options
- Adult
- Ceftriaxone 1–2 g daily plus azithromycin 500 mg daily; OR ceftriaxone 1–2 g daily plus levofloxacin 750 mg daily.
- Paediatric
- —
Without MRSA/Pseudomonas risk factors. For resistant-pathogen risks, apply Table 4 using local validation, cultures and reassessment.
Safety-net
- Under this 2019 guideline, antibiotic duration depends on clinical stability and is at least 5 days; complications or resistant pathogens may require longer treatment.[2]
Referral criteria
- Hypotension requiring vasopressors or respiratory failure requiring mechanical ventilationDirect ICU admission[2]
Clinical summary
ATS/IDSA 2019 guidance for adult CAP without immunocompromising conditions; select treatment by comorbidities, severity and validated resistant-pathogen risks.
References
- 1.ATS/IDSA 2019 Adult Community-acquired Pneumonia — Executive Summary (2019)
- 2.Diagnosis and Treatment of Adults with Community-acquired Pneumonia: An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. American Journal of Respiratory and Critical Care Medicine (2019)