What are the initial treatment recommendations for Community-Acquired Pneumonia (CAP)?

Initial Treatment Recommendations for Community-Acquired Pneumonia (CAP)

For community-acquired pneumonia, empiric antibiotic therapy should be based on the patient's risk factors, severity of illness, and treatment setting, with treatment initiated promptly after diagnosis. 1

Outpatient Treatment

Previously Healthy Patients (No Comorbidities)

• Amoxicillin 1 g every 8 hours is recommended as first-line therapy for outpatients without comorbidities 2
• Doxycycline 100 mg twice daily is an alternative first-line option for outpatients without comorbidities 2
• Some experts recommend that the first dose of oral doxycycline be 200 mg to achieve adequate serum levels more rapidly 2

Outpatients with Comorbidities or Recent Antibiotic Use

• A respiratory fluoroquinolone (levofloxacin or moxifloxacin) is recommended 1, 3
• Alternatively, a β-lactam plus a macrolide (such as amoxicillin-clavulanate plus azithromycin) is recommended 1, 3
• Patients with recent exposure to one class of antibiotics should receive treatment with antibiotics from a different class due to increased risk for bacterial resistance 2

Hospitalized Non-ICU Patients

• Standard regimen of β-lactam (such as ceftriaxone) plus a macrolide (such as azithromycin) is recommended 1, 4
• Alternatively, a respiratory fluoroquinolone alone (levofloxacin or moxifloxacin) can be used 2
• Treatment options include (in alphabetical order):
  • Aminopenicillin ± macrolide
  • Aminopenicillin/β-lactamase inhibitor ± macrolide
  • Non-antipseudomonal cephalosporin
  • Cefotaxime or ceftriaxone ± macrolide
  • Levofloxacin
  • Moxifloxacin
  • Penicillin G ± macrolide 2

Severe CAP/ICU Treatment

No Risk Factors for Pseudomonas

• Non-antipseudomonal cephalosporin III + macrolide OR
• Moxifloxacin or levofloxacin ± non-antipseudomonal cephalosporin III 2, 1

Risk Factors for Pseudomonas

• Antipseudomonal cephalosporin OR
• Acylureidopenicillin/β-lactamase inhibitor OR
• Carbapenem (meropenem preferred)
• PLUS ciprofloxacin OR
• PLUS macrolide + aminoglycoside (gentamicin, tobramycin or amikacin) 2, 1

Special Considerations

MRSA Coverage

• Add vancomycin or linezolid when community-acquired MRSA is suspected 1, 5
• Risk factors for MRSA include prior MRSA infection, recent hospitalization, or recent antibiotic use 1, 5

Timing of Administration

• For hospitalized patients, the first antibiotic dose should be administered while still in the emergency department 1, 5
• Antibiotic treatment should be initiated immediately after diagnosis of CAP 2

Duration of Therapy

• The minimum duration of therapy is 5 days for most patients 1, 5
• Treatment should generally not exceed 8 days in a responding patient 2
• Patients should be afebrile for 48-72 hours and have no more than one sign of clinical instability before discontinuing therapy 1, 5

Common Pitfalls and Caveats

• Overreliance on fluoroquinolones can lead to resistance; they should be reserved for patients with β-lactam allergies or when specifically indicated 1, 5
• Inadequate coverage for atypical pathogens (Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila) should be avoided 1, 6
• Failure to adjust therapy based on culture results can lead to unnecessary prolonged therapy; antimicrobial therapy should be directed at the specific pathogen once identified 1, 5
• Despite concerns regarding adverse events associated with fluoroquinolones, they remain justified for adults with comorbidities and CAP managed in the outpatient setting due to their performance in numerous studies, low resistance rates, coverage of both typical and atypical organisms, oral bioavailability, and convenience of monotherapy 2
• The U.S. Food and Drug Administration has issued warnings about increasing reports of adverse events related to fluoroquinolone use 2