What antibiotics are recommended for community-acquired pneumonia (CAP)?

From the Guidelines

For community-acquired pneumonia (CAP), the recommended antibiotics depend on the treatment setting and patient factors, with a focus on targeting the most common CAP pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and atypical organisms like Mycoplasma pneumoniae, as outlined in the 2019 American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) guideline 1.

Treatment Settings and Recommendations

• For outpatient treatment of healthy adults without risk factors, amoxicillin 1g three times daily for 5-7 days is typically first-line therapy, as it is active against 90%–95% of S. pneumoniae strains when used at a dosage of 3–4 g/day 1.
• Alternatives include doxycycline 100mg twice daily or a macrolide such as azithromycin 500mg on day 1, then 250mg daily for 4 more days, which are active against atypical agents and have been shown to have good clinical outcomes 1.
• For patients with comorbidities or recent antibiotic use, consider a respiratory fluoroquinolone like levofloxacin 750mg daily or a combination of amoxicillin-clavulanate plus a macrolide, as these regimens have been shown to be effective against a broader range of pathogens, including S. pneumoniae and H. influenzae 1.
• For hospitalized non-ICU patients, combination therapy with a beta-lactam (ampicillin-sulbactam, ceftriaxone, or cefotaxime) plus a macrolide is recommended, as this regimen provides broad coverage against common CAP pathogens, including S. pneumoniae and atypical organisms 1.
• For severe CAP requiring ICU admission, broader coverage with a beta-lactam plus either a respiratory fluoroquinolone or azithromycin is appropriate, as these regimens have been shown to be effective against a wide range of pathogens, including Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) 1.

Key Considerations

• Treatment should be adjusted based on culture results when available, and duration should typically be 5-7 days for most patients with clinical improvement, as outlined in the 2019 ATS/IDSA guideline 1.
• The choice of antibiotic should take into account the patient's risk factors for resistant organisms, such as recent antibiotic use or comorbidities, and the local epidemiology of CAP pathogens 1.
• The use of fluoroquinolones should be judicious, as there is concern for abuse and the development of resistance, particularly among S. pneumoniae and P. aeruginosa 1.

From the FDA Drug Label

1. 2 Community-Acquired Pneumonia: 7 to 14 Day Treatment Regimen Levofloxacin tablets are indicated for the treatment of community-acquired pneumonia due to methicillin-susceptible Staphylococcus aureus, Streptococcus pneumoniae (including multi-drug-resistant Streptococcus pneumoniae [MDRSP]), Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis, Chlamydophila pneumoniae, Legionella pneumophila, or Mycoplasma pneumoniae

DOSAGE & ADMINISTRATION SECTION Adults Infection *Recommended Dose/Duration of Therapy *DUE TO THE INDICATED ORGANISMS (See INDICATIONS AND USAGE.) Community-acquired pneumonia (mild severity) 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5

Recommended antibiotics for community-acquired pneumonia (CAP)

• Levofloxacin
• Azithromycin Key points:
• Levofloxacin is indicated for the treatment of CAP due to various organisms, including methicillin-susceptible Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae 2
• Azithromycin is recommended for the treatment of CAP (mild severity) with a dose of 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5 3

From the Research

Recommended Antibiotics for Community-Acquired Pneumonia (CAP)

The following antibiotics are recommended for the treatment of community-acquired pneumonia (CAP):

• Macrolides (e.g., azithromycin, erythromycin, clarithromycin) 4, 5, 6, 7
• Doxycycline 5, 6, 8
• Fluoroquinolones (e.g., levofloxacin, ofloxacin) 4, 5, 6, 8
• Beta-lactams (e.g., ceftriaxone, cefuroxime axetil, amoxicillin) 4, 6
• Combination therapy with a macrolide and a beta-lactam (e.g., ceftriaxone plus azithromycin) 4, 6

Treatment Regimens

Different treatment regimens are recommended for outpatients and hospitalized patients:

• Outpatients: monotherapy with a macrolide, doxycycline, or a fluoroquinolone 5, 6, 8, 7
• Hospitalized patients: combination therapy with a beta-lactam and a macrolide, or monotherapy with a fluoroquinolone 4, 6

Specific Antibiotic Combinations

Some studies have compared the efficacy of specific antibiotic combinations:

• Ceftriaxone plus azithromycin vs. levofloxacin: both regimens were effective, but the combination therapy had a higher bacteriological eradication rate for Streptococcus pneumoniae 4
• Doxycycline vs. levofloxacin: doxycycline was found to be an effective and economical alternative to levofloxacin for the treatment of CAP in general medical wards 8
• Azithromycin vs. amoxicillin-clavulanate: azithromycin 1g once daily for 3 days was found to be at least as effective as amoxicillin-clavulanate 875/125 mg twice daily for 7 days in the treatment of outpatients with CAP 7