What antibiotic is recommended for treating pneumonia?

From the Guidelines

For healthy outpatient adults without comorbidities, amoxicillin 1 g three times daily is recommended as the first-line treatment for community-acquired pneumonia. This recommendation is based on the strongest and most recent evidence from the American Thoracic Society and Infectious Diseases Society of America guideline published in 2019 1. The guideline suggests that amoxicillin is a strong recommendation with moderate quality of evidence, making it the preferred choice for treating pneumonia in healthy outpatient adults.

For outpatient adults with comorbidities, the guideline recommends combination therapy with amoxicillin/clavulanate and a macrolide, or monotherapy with a respiratory fluoroquinolone such as levofloxacin 1. The choice of antibiotic should be based on the patient's underlying conditions, such as chronic heart, lung, liver, or renal disease, and the presence of risk factors for antibiotic-resistant pathogens.

Key considerations for treating pneumonia include:

• The patient's age and underlying health conditions
• The severity of the pneumonia
• Local resistance patterns and the likelihood of antibiotic-resistant pathogens
• The need for combination therapy or monotherapy

In general, the goal of treatment is to target the most likely pathogens while minimizing the risk of antibiotic resistance and adverse effects. The use of amoxicillin as a first-line treatment for community-acquired pneumonia in healthy outpatient adults is supported by the most recent and highest-quality evidence 1.

From the FDA Drug Label

Treatment of pneumonia In the treatment of pneumonia, azithromycin has only been shown to be safe and effective in the treatment of community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae or Streptococcus pneumoniae in patients appropriate for oral therapy Levofloxacin tablets are indicated for the treatment of nosocomial pneumonia due to methicillin-susceptible Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae, or Streptococcus pneumoniae. 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 Mycoplasia pneumoniae

Recommended antibiotics for treating pneumonia are:

• Azithromycin (for community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Mycoplasia pneumoniae or Streptococcus pneumoniae) 2
• Levofloxacin (for nosocomial pneumonia due to methicillin-susceptible Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae, or Streptococcus pneumoniae, and for community-acquired pneumonia due to methicillin-susceptible Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis, Chlamydophila pneumoniae, Legionella pneumophila, or Mycoplasia pneumoniae) 3

From the Research

Recommended Antibiotics for Treating Pneumonia

• The recommended optimal in-hospital therapy for community-acquired pneumonia is a beta-lactam antibiotic (penicillin, aminopenicillin, cefotaxime, or ceftriaxone) administered with a macrolide or a fluoroquinolone agent for adjunctive treatment of infection with potential atypical pathogens 4.
• Combination therapy with a third-generation cephalosporin and a macrolide is at least as efficacious as monotherapy with a fluoroquinolone with enhanced anti-pneumococcal activity, for hospitalized patients with moderate to severe community-acquired pneumonia 5.
• Combination antibiotic therapy achieves a better outcome compared with monotherapy and should be given to patients with community-acquired pneumonia who have comorbidities, previous antibiotic therapy, or severe CAP 6.

Specific Antibiotic Combinations

• Ceftriaxone plus azithromycin is a recommended combination for hospitalized patients with moderate to severe community-acquired pneumonia, with a favorable clinical outcome in 91.5% of patients 5.
• Azithromycin may be the first-choice macrolide for treatment of community-acquired pneumonia, with a shorter treatment course resulting in better compliance with therapy and improved outcomes compared to clarithromycin 7.

Treatment Guidelines

• International community-acquired pneumonia treatment guidelines acknowledge the combination of a third-generation cephalosporin and a macrolide as at least as efficacious as monotherapy with a fluoroquinolone for hospitalized patients with moderate to severe CAP 5.
• Medical-specialty professional societies suggest that combination therapy with a beta-lactam plus a macrolide or doxycycline or monotherapy with a "respiratory quinolone" are optimal first-line therapy for patients hospitalized with community-acquired pneumonia 8.