What are the recommended antibiotics for treating pneumonia?

Recommended Antibiotics for Treating Pneumonia

For community-acquired pneumonia (CAP), the first-line treatment is amoxicillin plus a macrolide (clarithromycin or azithromycin), with fluoroquinolones reserved as alternative options for those with penicillin allergies or treatment failures. 1

Community-Acquired Pneumonia (CAP)

Non-Severe CAP (Outpatient Treatment)

• First-line: Amoxicillin as monotherapy for previously untreated patients 1
• Alternative: Macrolide (clarithromycin or azithromycin) for patients with penicillin allergies or who have failed amoxicillin treatment 1
• Duration: Generally 7-8 days for responding patients 1

Non-Severe CAP (Hospitalized Patients)

• First-line: Combined oral therapy with amoxicillin and a macrolide (clarithromycin or azithromycin) 1
• When oral treatment is contraindicated: Intravenous ampicillin or benzylpenicillin, together with erythromycin or clarithromycin 1
• Alternative (for penicillin/macrolide intolerance): Fluoroquinolone with enhanced pneumococcal activity (levofloxacin) 1, 2
• Duration: 7-10 days for microbiologically undefined pneumonia 1

Severe CAP (Requiring ICU)

• First-line: Intravenous combination of a broad-spectrum β-lactamase stable antibiotic (co-amoxiclav, cefuroxime, or cefotaxime/ceftriaxone) plus a macrolide (clarithromycin or erythromycin) 1
• Alternative (for β-lactam/macrolide intolerance): Fluoroquinolone with enhanced pneumococcal activity (levofloxacin) plus intravenous benzylpenicillin 1, 2
• Duration: 10-14 days, extended to 14-21 days for legionella, staphylococcal, or Gram-negative enteric bacilli pneumonia 1

Pathogen-Specific Considerations

Atypical Pathogens

• Mycoplasma pneumoniae: Macrolides (azithromycin or clarithromycin), tetracyclines (doxycycline), or fluoroquinolones (levofloxacin or moxifloxacin) 1
• Chlamydophila pneumoniae: Azithromycin (preferred), other macrolides, fluoroquinolones, or tetracyclines 1, 3
• Legionella species: Levofloxacin or azithromycin (newer macrolides preferred over erythromycin) 1

Gram-Negative Pathogens

• Haemophilus influenzae: Second/third generation cephalosporins or fluoroquinolones for β-lactamase producing strains 1
• Klebsiella pneumoniae: Third-generation cephalosporins (cefotaxime, ceftriaxone) 1
• Pseudomonas aeruginosa: Antipseudomonal cephalosporin or acylureidopenicillin/β-lactamase inhibitor or carbapenem PLUS ciprofloxacin OR macrolide plus aminoglycoside 1

Special Considerations

Treatment Failure

• For non-severe pneumonia initially treated with amoxicillin monotherapy: Add or substitute a macrolide 1
• For non-severe pneumonia on combination therapy: Consider changing to a fluoroquinolone with effective pneumococcal coverage 1
• For severe pneumonia not responding to combination treatment: Consider adding rifampicin 1

Aspiration Pneumonia

• Hospital ward (admitted from home): Oral or IV β-lactam/β-lactamase inhibitor, clindamycin, IV cephalosporin + oral metronidazole, or moxifloxacin 1
• ICU or nursing home patients: Clindamycin + cephalosporin 1
• For high mortality risk patients: Piperacillin-tazobactam 4.5g IV every 6 hours 4

Transition from IV to Oral Therapy

• Sequential treatment should be considered in all patients except the most severely ill 1
• Switch to oral treatment when clinical stability is achieved, even in patients with severe pneumonia 1
• Decision should be guided by resolution of the most prominent clinical features present at admission 1

Common Pitfalls to Avoid

• Using fluoroquinolones as first-line agents when not indicated (reserve for specific situations) 1
• Inadequate coverage for atypical pathogens in empiric therapy 1, 5
• Failure to adjust therapy based on local resistance patterns 1, 6
• Unnecessarily prolonged antibiotic courses when shorter durations may be effective 1, 7
• Delaying antibiotic administration in severe pneumonia (should be given immediately after diagnosis) 1