What is the initial treatment for community-acquired pneumonia (CAP)?

From the Guidelines

The initial treatment for community-acquired pneumonia (CAP) should be empiric antibiotic therapy, with the choice of antibiotics depending on the setting and patient factors, prioritizing the most recent and highest quality evidence from 2023 1.

Key Considerations

• For outpatient treatment of previously healthy individuals, a short course of antibiotics (≤ 6 days) is as effective as long courses, with fewer serious adverse events and low mortality 1.
• Alternatives for patients with penicillin allergies include doxycycline or a macrolide such as azithromycin.
• For patients with comorbidities or recent antibiotic use, a respiratory fluoroquinolone or combination therapy with amoxicillin-clavulanate plus a macrolide is preferred.

Treatment Options

• Outpatient treatment: amoxicillin 1 gram three times daily for 5-7 days, or alternatives such as doxycycline 100 mg twice daily or azithromycin 500 mg on day one followed by 250 mg daily for 4 more days.
• Hospitalized non-ICU patients: a beta-lactam (ceftriaxone 1-2 g daily or ampicillin-sulbactam 3 g every 6 hours) plus a macrolide.
• ICU patients: may require broader coverage, including vancomycin and piperacillin-tazobactam, depending on the severity of illness and risk factors for drug-resistant pathogens 1.

Important Notes

• Treatment should begin promptly after diagnosis, ideally after obtaining appropriate cultures but without delaying antibiotics.
• Reassessment within 48-72 hours is essential to evaluate clinical response and potentially narrow therapy based on culture results.
• The choice of antibiotics targets the most common CAP pathogens, including Streptococcus pneumoniae, Haemophilus influenzae, and atypical organisms like Mycoplasma pneumoniae.

From the FDA Drug Label

Azithromycin for Injection, USP is indicated for the treatment of patients with infections caused by susceptible strains of the designated microorganisms in the conditions listed below... Community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Legionella pneumophila, Moraxella catarrhalis, Mycoplasma pneumoniae, Staphylococcus aureus, or Streptococcus pneumoniae in patients who require initial intravenous therapy

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

The initial treatment for community-acquired pneumonia (CAP) is azithromycin, which can be administered intravenously or orally, depending on the severity of the infection.

• For patients who require initial intravenous therapy, azithromycin for injection is indicated.
• For patients with mild severity CAP, the recommended dose is 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5 2 3. Key points:
• Azithromycin is effective against various microorganisms that cause CAP.
• The dosage and duration of therapy may vary depending on the severity of the infection and the patient's response to treatment.

From the Research

Initial Treatment for Community-Acquired Pneumonia (CAP)

The initial treatment for community-acquired pneumonia (CAP) typically involves the use of antibiotics, with the choice of antibiotic depending on various factors such as the severity of the disease, the presence of comorbidities, and the likelihood of antibiotic resistance 4.

Antibiotic Options

Some of the commonly used antibiotics for the treatment of CAP include:

• Beta-lactams, such as ceftriaxone, which have historically been considered standard therapy for CAP 4
• Macrolides, such as azithromycin, which are often used in combination with beta-lactams 4, 5
• Fluoroquinolones, such as levofloxacin, which are broad-spectrum antibiotics that exhibit high levels of penetration into the lungs and low levels of resistance 4, 6, 7
• Doxycycline, which has been shown to be an effective and economical alternative to levofloxacin in the empirical treatment of CAP 6

Treatment Regimens

Some studies have compared different treatment regimens for CAP, including:

• Ceftriaxone plus azithromycin versus ceftriaxone plus clarithromycin or erythromycin 5
• Levofloxacin versus doxycycline 6
• High-dose levofloxacin versus combined ceftriaxone and azithromycin 7

New Antibiotics

There are also new antibiotics being developed for the treatment of CAP, including delafloxacin, omadacycline, lefamulin, solithromycin, nemonoxacin, and ceftaroline, which have activity against methicillin-resistant Staphylococcus aureus and macrolide-resistant Streptococcus pneumoniae 8.

Key Findings

Some key findings from these studies include:

• Clinical success rates of > 90% for moxifloxacin, gatifloxacin, and levofloxacin in the treatment of CAP due to Streptococcus pneumoniae 4
• Equivalent efficacy and safety of ceftriaxone/azithromycin and ceftriaxone/clarithromycin or erythromycin in the treatment of hospitalized patients with CAP 5
• Doxycycline as an effective and economical alternative to levofloxacin in the empirical treatment of CAP 6
• High-dose levofloxacin as a single-agent therapy for CAP, with excellent clinical and microbiological efficacy and a safety profile comparable to that of ceftriaxone plus azithromycin therapy 7