Latest Guidelines for Pneumonia Management
Community-Acquired Pneumonia (CAP)
Outpatient Treatment
For previously healthy adults without comorbidities or recent antibiotic use, amoxicillin 1g three times daily is the preferred first-line treatment 1. This represents a shift toward high-dose beta-lactam monotherapy in low-risk patients.
Alternative outpatient regimens for healthy patients include:
- Doxycycline 100 mg twice daily (though recent evidence suggests azithromycin may be superior when combined with beta-lactams) 1, 2
- Macrolides (azithromycin 500 mg day 1, then 250 mg daily; or clarithromycin 500 mg twice daily) only in areas where pneumococcal macrolide resistance is <25% 1
For patients with comorbidities (chronic heart, lung, liver, or renal disease; diabetes; alcoholism; malignancy; asplenia) or recent antibiotic use, combination therapy or fluoroquinolone monotherapy is required 1, 3:
- Combination therapy: Amoxicillin/clavulanate (875/125 mg twice daily or 2000/125 mg twice daily) OR cephalosporin (cefpodoxime 200 mg twice daily or cefuroxime 500 mg twice daily) PLUS a macrolide or doxycycline 1
- Monotherapy: Respiratory fluoroquinolone (levofloxacin 750 mg daily, moxifloxacin 400 mg daily, or gemifloxacin 320 mg daily) 1
Hospitalized Non-Severe CAP
Most hospitalized patients with non-severe CAP can be treated with oral antibiotics 1. The preferred regimen is combination therapy with amoxicillin plus a macrolide (azithromycin or clarithromycin) 1, 3.
When oral therapy is contraindicated, use intravenous ampicillin or benzylpenicillin plus erythromycin or clarithromycin 1.
Alternative regimens for hospitalized non-severe CAP include 1:
- Aminopenicillin/beta-lactamase inhibitor ± macrolide
- Non-antipseudomonal cephalosporin (cefotaxime or ceftriaxone) ± macrolide
- Levofloxacin or moxifloxacin monotherapy
A critical caveat: Recent evidence from a large matched cohort study (2025) demonstrates that azithromycin combined with beta-lactams results in significantly lower mortality (OR 0.71) and more hospital-free days compared to doxycycline combined with beta-lactams 2. This suggests azithromycin should be preferred over doxycycline when combination therapy is used.
Severe CAP (ICU or Intermediate Care)
Patients with severe pneumonia require immediate parenteral antibiotics 1. The 2019 ATS/IDSA guidelines recommend using the 2007 IDSA/ATS severe CAP criteria to identify patients requiring ICU-level care 1, 3.
For severe CAP without Pseudomonas risk factors, use:
- Non-antipseudomonal cephalosporin III (cefotaxime or ceftriaxone) PLUS macrolide 1
- OR moxifloxacin or levofloxacin ± non-antipseudomonal cephalosporin III 1
The preferred regimen is intravenous co-amoxiclav or second-generation cephalosporin (cefuroxime) or third-generation cephalosporin (cefotaxime or ceftriaxone) combined with a macrolide (clarithromycin or erythromycin) 1.
For severe CAP with Pseudomonas risk factors, use:
- Antipseudomonal cephalosporin OR acylureidopenicillin/beta-lactamase inhibitor OR carbapenem (meropenem preferred, up to 6g daily in 3×2g 3-hour infusions) 1
- PLUS ciprofloxacin 1
- OR PLUS macrolide + aminoglycoside (gentamicin, tobramycin, or amikacin) 1
For patients with MRSA risk factors, add vancomycin or linezolid 3, 4.
Treatment Duration and Monitoring
Treatment duration should generally not exceed 8 days in responding patients 1. Patients should be treated for a minimum of 5 days 3. Biomarkers, particularly procalcitonin, may guide shorter treatment duration 1.
For severe microbiologically undefined pneumonia, 10 days of treatment is recommended, extended to 14-21 days for confirmed Legionella, staphylococcal, or Gram-negative enteric bacilli pneumonia 1.
Antibiotic treatment should be initiated immediately after diagnosis 1. For hospitalized patients, the first antibiotic dose should be administered in the emergency department to minimize time to treatment 3.
Switch from intravenous to oral antibiotics is appropriate after clinical improvement and ability to tolerate oral medications, typically within the first 3 days 3, 5.
Failure to Improve
For patients not improving as expected, conduct a careful clinical review including examination, prescription chart review, and all investigation results 1.
Consider repeat chest radiograph, CRP, white cell count, and additional microbiological specimens 1.
For non-severe pneumonia on amoxicillin monotherapy, add or substitute a macrolide 1. For those on combination therapy, switching to a fluoroquinolone with pneumococcal coverage is an option 1. For severe pneumonia not responding to combination antibiotics, consider adding rifampicin 1.
Follow-up
Clinical review should be arranged at approximately 6 weeks 1. Chest radiograph at follow-up is indicated for patients with persistent symptoms/signs or those at higher risk for malignancy (smokers and those >50 years) 1. Follow-up imaging is not routinely needed for patients whose symptoms resolve within 5-7 days 3.
Hospital-Acquired Pneumonia (HAP)
The 2025 guidelines recommend abandoning the healthcare-associated pneumonia (HCAP) category 3. Instead, empirically cover MRSA or Pseudomonas aeruginosa only when locally validated risk factors are present 3.
For suspected MRSA, use vancomycin or linezolid as empiric treatment 3, 4.
For suspected Pseudomonas aeruginosa, use piperacillin-tazobactam, cefepime, ceftazidime, aztreonam, meropenem, or imipenem as empiric treatment 3.
Two diagnostic strategies are recognized: clinical strategy and bacteriologic strategy 3. De-escalation of therapy should be based on microbiologic cultures and clinical response 3.
Key Pitfalls to Avoid
- Do not use fluoroquinolones as first-line agents in the community setting 1, though they are valuable alternatives for hospitalized patients with specific indications
- Do not delay antibiotic administration—immediate treatment after diagnosis improves outcomes 1, 3
- Do not continue antibiotics beyond 8 days in responding patients unless specific pathogens (Legionella, Staphylococcus, Gram-negative bacilli) are confirmed 1
- Do not routinely use anti-MRSA or antipseudomonal coverage for HAP without validated risk factors—this represents a major shift from older HCAP guidelines 3
- Avoid doxycycline when azithromycin is available for combination therapy with beta-lactams, as recent evidence shows superior outcomes with azithromycin 2