First-Line Treatment for Community-Acquired Pneumonia (CAP)
The first-line treatment for community-acquired pneumonia (CAP) is a combination of a beta-lactam (such as amoxicillin, ceftriaxone, or ampicillin) plus a macrolide (such as azithromycin or clarithromycin), with specific regimens determined by severity and treatment setting. 1
Treatment Based on Severity and Setting
Outpatient Treatment (Non-Severe CAP)
Previously healthy patients with no risk factors:
Patients with comorbidities or risk factors for drug-resistant S. pneumoniae:
Hospitalized Patients (Non-Severe CAP)
- Combined oral therapy with amoxicillin and a macrolide (erythromycin or clarithromycin) 2
- When oral treatment is contraindicated: IV ampicillin or benzylpenicillin, together with erythromycin or clarithromycin 2
- For penicillin-allergic patients: Respiratory fluoroquinolone (levofloxacin is currently the only recommended agent licensed in the UK) 2
Hospitalized Patients (Severe CAP)
- IV combination of a broad-spectrum β-lactamase stable antibiotic (co-amoxiclav, cefuroxime, cefotaxime, or ceftriaxone) together with a macrolide (clarithromycin or erythromycin) 2, 1
- For penicillin-allergic patients: Fluoroquinolone with enhanced activity against S. pneumoniae (levofloxacin) together with IV benzylpenicillin 2
Treatment Duration
- Standard course: 7-10 days for most patients 1
- Minimum: 5 days, continuing until the patient is afebrile for 48-72 hours and has no more than one sign of clinical instability 1
- Extended course (14-21 days): For legionella, staphylococcal, or Gram-negative enteric bacilli pneumonia 2, 1
Special Considerations
Pseudomonas aeruginosa Suspicion
- Antipseudomonal beta-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either:
- Ciprofloxacin/levofloxacin, OR
- Aminoglycoside plus azithromycin, OR
- Aminoglycoside plus an antipneumococcal fluoroquinolone 1
MRSA Suspicion
- Add vancomycin or linezolid to the standard regimen 1
Management of Treatment Failure
- Review clinical history, examination, and all available test results 2, 1
- Consider additional investigations (repeat chest radiograph, CRP, WBC) 2, 1
- For non-severe CAP with amoxicillin monotherapy: Add or substitute a macrolide 2
- For non-severe CAP with combination therapy: Consider switching to a fluoroquinolone 2
- For severe CAP not responding to combination therapy: Consider adding rifampicin 2
Transition from IV to Oral Therapy
- Switch when the patient shows clinical improvement, is hemodynamically stable, and can tolerate oral medications 1
- Typically after 1-2 days of IV therapy if the patient is showing appropriate clinical improvement 1
Monitoring and Follow-up
- Monitor temperature, respiratory rate, pulse, blood pressure, mental status, and oxygen saturation at least twice daily 1
- Clinical review should be arranged for all patients at around 6 weeks 2
- Repeat chest radiograph for patients with persistent symptoms or physical signs, especially smokers and those over 50 years 2
Important Caveats
- In regions with high-level macrolide resistance (>25%), consider alternative regimens 1
- Recent antibiotic use should be taken into account when selecting an agent; choose from a different class than what the patient received in the previous 3 months 1
- Fluoroquinolones (like levofloxacin and moxifloxacin) are not recommended as first-line agents or for community use for pneumonia but may provide a useful alternative in selected hospitalized patients 2
- For influenza co-infection, add oseltamivir if suspected or confirmed 1
The combination of a beta-lactam plus a macrolide has shown superior outcomes in terms of mortality and morbidity compared to monotherapy, particularly for patients with more severe disease or significant comorbidities 1, 3.