What is the exact treatment for pneumonia?

Treatment of Pneumonia

For community-acquired pneumonia (CAP), treatment depends critically on disease severity and setting: healthy outpatients without comorbidities should receive amoxicillin 1g three times daily, while hospitalized patients with non-severe CAP require combination therapy with amoxicillin plus a macrolide (azithromycin or clarithromycin), and severe CAP demands immediate IV β-lactam/macrolide combination therapy such as ceftriaxone with azithromycin. 1

Outpatient Treatment (Community Setting)

Healthy Adults Without Comorbidities

First-line monotherapy options include:

• Amoxicillin 1g three times daily (preferred first-line agent) 1
• Doxycycline 100mg twice daily (alternative option) 1
• Macrolide monotherapy (azithromycin 500mg day 1, then 250mg daily for 4 days OR clarithromycin 500mg twice daily) - only in areas where pneumococcal macrolide resistance is <25% 1

The preference for amoxicillin reflects its excellent coverage of Streptococcus pneumoniae, which remains the most common bacterial pathogen identified in CAP (approximately 15% of cases with identified etiology) 2. Penicillin G and its derivatives remain the drugs of choice for pneumococcal infections in most regions 1.

Outpatients With Comorbidities

For patients with chronic heart, lung, liver, or renal disease; diabetes; alcoholism; malignancy; or asplenia, combination therapy or respiratory fluoroquinolone monotherapy is required 1:

Combination therapy (preferred):

• Amoxicillin/clavulanate (500/125mg three times daily OR 875/125mg twice daily OR 2000/125mg twice daily) PLUS a macrolide (azithromycin or clarithromycin) 1
• OR cephalosporin (cefpodoxime 200mg twice daily OR cefuroxime 500mg twice daily) PLUS a macrolide or doxycycline 1

Monotherapy alternative:

• Respiratory fluoroquinolone: levofloxacin 750mg daily, moxifloxacin 400mg daily, or gemifloxacin 320mg daily 1

Hospitalized Patients - Non-Severe CAP

Most hospitalized patients with non-severe CAP can be treated with oral antibiotics 1. The preferred regimen is combination therapy with oral amoxicillin PLUS a macrolide (erythromycin or clarithromycin) 1.

When oral therapy is contraindicated, use IV ampicillin or benzylpenicillin PLUS IV erythromycin or clarithromycin 1.

Fluoroquinolones with enhanced pneumococcal activity (levofloxacin) provide an alternative for patients intolerant of penicillins or macrolides, though they are not recommended as first-line agents 1.

Hospitalized Patients - Severe CAP

Patients with severe pneumonia require immediate parenteral antibiotics within 24 hours of diagnosis 1, 2.

Preferred regimen:

• IV β-lactam (co-amoxiclav OR cefuroxime OR cefotaxime OR ceftriaxone) PLUS IV macrolide (clarithromycin or erythromycin) 1, 2

Alternative for β-lactam or macrolide intolerance:

• Fluoroquinolone with enhanced S. pneumoniae activity (levofloxacin) PLUS IV benzylpenicillin 1

Systemic corticosteroids administered within 24 hours of severe CAP development may reduce 28-day mortality 2.

Duration of Therapy

For uncomplicated S. pneumoniae pneumonia: 7-10 days total 1. However, hospitalized patients can be treated for a minimum of 3 days if clinically stable 2.

For severe microbiologically undefined pneumonia: 10 days 1. Extend to 14-21 days when Legionella, staphylococcal, or gram-negative enteric bacilli are suspected or confirmed 1.

For S. pneumoniae bacteremia: IV antibiotics for 5-7 days followed by oral step-down therapy, with total duration of 7-10 days in responding patients 3. Recent evidence supports that total treatment should generally not exceed 8 days in responding patients 3.

Switching from IV to oral therapy after 5-7 days is increasingly accepted practice 1, and switching to oral treatment after reaching clinical stability is safe even in severe pneumonia 3.

Pathogen-Specific Therapy

When specific pathogens are identified, targeted therapy should be employed:

• S. pneumoniae: Penicillin G or ampicillin (for non-β-lactamase producers) 1
• H. influenzae (non-β-lactamase producing): Ampicillin 1
• M. pneumoniae* or *C. pneumoniae: Macrolide (erythromycin, azithromycin, clarithromycin) or tetracycline 1
• Legionella: Erythromycin 1
• Aspiration pneumonia (community-acquired): Penicillin G; alternatives include lincosamide or penicillin/β-lactamase inhibitor combination 1
• Methicillin-sensitive S. aureus: Semisynthetic penicillinase-resistant penicillin 1

Nosocomial Pneumonia

For ventilator-associated or nosocomial pneumonia, combination therapy with an extended-spectrum penicillin or cephalosporin PLUS an aminoglycoside is commonly employed 1. Initial therapy must be directed at suspected pathogens based on the specific hospital's known susceptibility patterns 1.

Testing and Diagnostic Considerations

All patients with CAP should be tested for COVID-19 and influenza when these viruses are circulating in the community, as their diagnosis affects treatment and infection prevention strategies 2. Only 38% of hospitalized CAP patients have a pathogen identified, with up to 40% of identified cases being viral 2.

Failure to Improve

For patients failing to improve, conduct a careful clinical review by an experienced clinician, including examination, prescription review, and all investigation results 1. Obtain repeat chest radiograph, CRP, white cell count, and additional microbiological specimens 1.

Treatment modifications for non-responders:

• Non-severe pneumonia on amoxicillin monotherapy: Add or substitute a macrolide 1
• Non-severe pneumonia on combination therapy: Consider switching to a fluoroquinolone with pneumococcal coverage 1
• Severe pneumonia not responding to combination therapy: Consider adding rifampicin 1

Critical Pitfalls to Avoid

Do not use azithromycin monotherapy in patients with pneumonia judged inappropriate for oral therapy, including those with cystic fibrosis, nosocomial infections, known/suspected bacteremia, requiring hospitalization, elderly/debilitated patients, or those with immunodeficiency or functional asplenia 4.

Be aware of QT prolongation risk with macrolides (especially azithromycin) in patients with known QT prolongation, torsades de pointes history, congenital long QT syndrome, bradyarrhythmias, uncompensated heart failure, or those on QT-prolonging drugs 4.

Consider local antimicrobial resistance patterns, as regional differences exist (e.g., higher penicillin resistance in S. pneumoniae in some geographic areas) 1.