What is the recommended treatment for pneumonia?

Treatment for Pneumonia

Outpatient Treatment

For previously healthy adults without comorbidities, amoxicillin 1 g orally three times daily for 5-7 days is the preferred first-line therapy, providing excellent coverage against Streptococcus pneumoniae including drug-resistant strains. 1

• Doxycycline 100 mg orally twice daily serves as an acceptable alternative for patients who cannot tolerate amoxicillin 1, 2
• Macrolides (azithromycin 500 mg day 1, then 250 mg daily for days 2-5; or clarithromycin 500 mg twice daily) should ONLY be used when local pneumococcal macrolide resistance is documented <25% 1, 2

Outpatients with Comorbidities

For patients with comorbidities (COPD, diabetes, chronic heart/liver/renal disease, malignancy) or recent antibiotic use within 3 months, combination therapy is required. 1, 2

• Preferred regimen: β-lactam (amoxicillin-clavulanate 875/125 mg twice daily, cefpodoxime, or cefuroxime) PLUS macrolide (azithromycin or clarithromycin) or doxycycline 1, 2
• Alternative: Respiratory fluoroquinolone monotherapy (levofloxacin 750 mg daily, moxifloxacin 400 mg daily, or gemifloxacin 320 mg daily) 1, 2, 3

Hospitalized Non-ICU Patients

For hospitalized patients not requiring ICU admission, two equally effective regimens exist: ceftriaxone 1-2 g IV daily PLUS azithromycin 500 mg IV or oral daily, or respiratory fluoroquinolone monotherapy (levofloxacin 750 mg IV daily or moxifloxacin 400 mg IV daily). 1, 2

• Alternative β-lactams: cefotaxime 1-2 g IV every 8 hours OR ampicillin-sulbactam 3 g IV every 6 hours, always combined with azithromycin 1, 2
• For penicillin-allergic patients, respiratory fluoroquinolone is the preferred alternative 1, 2
• The first antibiotic dose MUST be administered in the emergency department—delayed administration beyond 8 hours increases 30-day mortality by 20-30% 1, 2

Severe CAP Requiring ICU Admission

Combination therapy is mandatory for all ICU patients: β-lactam (ceftriaxone 2 g IV daily, cefotaxime 1-2 g IV every 8 hours, or ampicillin-sulbactam 3 g IV every 6 hours) PLUS either azithromycin 500 mg IV daily OR respiratory fluoroquinolone (levofloxacin 750 mg IV daily or moxifloxacin 400 mg IV daily). 1, 2

• Monotherapy is inadequate for severe disease and associated with higher mortality 1, 2
• For penicillin-allergic ICU patients: aztreonam 2 g IV every 8 hours PLUS azithromycin 500 mg IV daily OR levofloxacin 750 mg IV daily 1, 2

Special Pathogen Coverage

Pseudomonas aeruginosa Risk Factors

Add antipseudomonal coverage ONLY when specific risk factors are present: structural lung disease (bronchiectasis), recent hospitalization with IV antibiotics within 90 days, or prior respiratory isolation of P. aeruginosa. 1, 2

• Regimen: Antipseudomonal β-lactam (piperacillin-tazobactam 4.5 g IV every 6 hours, cefepime 2 g IV every 8 hours, imipenem, or meropenem) PLUS ciprofloxacin 400 mg IV every 8 hours OR levofloxacin 750 mg IV daily PLUS aminoglycoside (gentamicin or tobramycin 5-7 mg/kg IV daily) 1, 2

MRSA Risk Factors

Add MRSA coverage ONLY when specific risk factors are present: prior MRSA infection/colonization, recent hospitalization with IV antibiotics, post-influenza pneumonia, or cavitary infiltrates on imaging. 1, 2

• Regimen: Add vancomycin 15 mg/kg IV every 8-12 hours (target trough 15-20 mg/mL) OR linezolid 600 mg IV every 12 hours to the base regimen 1, 2

Duration of Therapy

Treat for a minimum of 5 days AND until the patient is afebrile for 48-72 hours with no more than one sign of clinical instability. 1, 2

• Typical duration for uncomplicated CAP: 5-7 days 1, 2
• Extended duration (14-21 days) required for: Legionella pneumophila, Staphylococcus aureus, or Gram-negative enteric bacilli 1, 2
• NEVER extend therapy beyond 7-8 days in responding patients without specific indications—this increases antimicrobial resistance risk without improving outcomes 1

Transition to Oral Therapy

Switch from IV to oral antibiotics when the patient is hemodynamically stable, clinically improving, able to ingest medications, and has normal gastrointestinal function—typically by day 2-3 of hospitalization. 1, 2

• Oral step-down options: amoxicillin 1 g three times daily PLUS azithromycin 500 mg daily, OR amoxicillin-clavulanate 875/125 mg twice daily PLUS azithromycin, OR doxycycline 100 mg twice daily alone 1, 2
• Levofloxacin 750 mg orally once daily is appropriate for penicillin-allergic patients 1, 3

Diagnostic Testing

Obtain blood cultures (two sets), sputum Gram stain and culture BEFORE initiating antibiotics in ALL hospitalized patients to allow pathogen-directed therapy and de-escalation. 1, 2

• Urinary antigen testing for Legionella pneumophila serogroup 1 should be obtained in severe CAP or ICU patients 1

Special Populations

Pregnant Women

For pregnant women, use β-lactam (amoxicillin or ceftriaxone) PLUS azithromycin (preferred macrolide in pregnancy). 1

• Azithromycin is preferred over clarithromycin because it did not produce birth defects in animal studies, whereas clarithromycin showed increased risk 1

COPD or Asthma Patients

Patients with COPD or asthma require combination therapy even in the outpatient setting due to increased risk of Pseudomonas aeruginosa and resistant pathogens. 1, 2

Critical Pitfalls to Avoid

• NEVER use macrolide monotherapy in hospitalized patients—provides inadequate coverage for typical bacterial pathogens like S. pneumoniae 1, 2
• NEVER delay antibiotic administration beyond 8 hours—increases mortality 1, 2
• NEVER use macrolides in areas where pneumococcal macrolide resistance exceeds 25%—leads to treatment failure 1, 2
• NEVER automatically add broad-spectrum antibiotics without documented risk factors for Pseudomonas or MRSA 1, 2

Follow-Up

• Clinical review at 48 hours or sooner if clinically indicated for outpatients 1
• Scheduled clinical review at 6 weeks for all hospitalized patients 1
• Chest radiograph at 6 weeks ONLY for patients with persistent symptoms, physical signs, or high risk for underlying malignancy (smokers, age >50 years) 1
• Chest radiograph is NOT required before hospital discharge in patients with satisfactory clinical recovery 1

Prevention

• Pneumococcal vaccination: 20-valent pneumococcal conjugate vaccine alone OR 15-valent pneumococcal conjugate vaccine followed by 23-valent pneumococcal polysaccharide vaccine one year later for all patients ≥65 years and those with high-risk conditions 1
• Annual influenza vaccination for all patients, especially those with medical illnesses 1
• Smoking cessation as a goal for all patients hospitalized with CAP who smoke 1