Drugs to treat pneumonia
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pneumonia antibiotic treatment guidelines 2025 CAP HAP empiric therapy
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Drugs to Treat Pneumonia
Pneumonia treatment depends on the type (community-acquired vs. hospital-acquired vs. special forms), severity, and likely/confirmed pathogen. Below is a structured breakdown drawn from The Washington Manual of Medical Therapeutics, Goldman-Cecil Medicine, and Fishman's Pulmonary Diseases.
1. Community-Acquired Pneumonia (CAP)
Outpatient (Mild, No Comorbidities)
| Regimen | Drug | Dose |
|---|---|---|
| Monotherapy | Amoxicillin | 1000 mg PO every 8 h, ≥5 days |
| Monotherapy | Doxycycline | 100 mg PO every 12 h, ≥5 days |
| Monotherapy | Azithromycin | 500 mg PO day 1, then 250 mg/day days 2-5 |
Outpatient (With Comorbidities - COPD, DM, heart/liver/renal disease, malignancy, asplenia)
- Beta-lactam (amoxicillin-clavulanate 875/125 mg PO q12h, OR cefpodoxime 200 mg PO q12h, OR cefuroxime 500 mg PO q12h) PLUS doxycycline or azithromycin
- OR Respiratory fluoroquinolone monotherapy: levofloxacin 750 mg PO daily or moxifloxacin 400 mg PO daily
Inpatient - Non-Severe
- Beta-lactam (ampicillin-sulbactam 1.5-3 g IV q6h, OR ceftriaxone 1-2 g IV daily, OR cefotaxime 1-2 g IV q8h, OR ceftaroline 600 mg IV q12h) PLUS a macrolide (azithromycin)
- OR Respiratory fluoroquinolone monotherapy (levofloxacin or moxifloxacin)
Inpatient - Severe CAP (ICU)
- Beta-lactam PLUS macrolide
- OR Beta-lactam PLUS fluoroquinolone
CAP with MRSA Risk Factors
Add: Vancomycin 15 mg/kg IV q12h (adjust by levels) OR Linezolid 600 mg IV/PO q12h
CAP with Pseudomonas aeruginosa Risk Factors
Add: Piperacillin-tazobactam 4.5 g IV q6-8h OR cefepime OR anti-pseudomonal fluoroquinolone
- Washington Manual of Medical Therapeutics, Table 14-9
Typical treatment duration: 5 days for most CAP (a 2025 Lancet Infectious Diseases umbrella review, PMID 39243792 supports shorter courses for respiratory tract infections).
2. Hospital-Acquired Pneumonia (HAP) / Ventilator-Associated Pneumonia (VAP)
Group A - No MDR risk factors, early-onset
| Drug | Dose |
|---|---|
| Ceftriaxone | 1-2 g IV/IM every 12-24 h |
| Levofloxacin | 750 mg IV daily |
| Ciprofloxacin | 400 mg IV every 8 h |
| Moxifloxacin | 400 mg IV/PO daily |
| Ampicillin-sulbactam | 1.5-3 g IV/IM every 6 h |
| Ertapenem | 1 g IV/IM once daily |
Group B - Late-onset or MDR Risk Factors
Two-drug regimens targeting Pseudomonas, MRSA, ESBL-producing Klebsiella, and Acinetobacter:
Anti-pseudomonal beta-lactams (choose one):
- Ceftazidime 2 g IV q8h
- Cefepime 1-2 g IV q8-12h
- Ceftazidime-avibactam 2.5 g IV q8h
- Ceftolozane-tazobactam 3 g IV q8h
- Cefiderocol 3 g IV q8h
- Meropenem 1 g IV q8h
- Imipenem 500 mg IV q6h or imipenem-relebactam 1.25 g q6h
- Piperacillin-tazobactam 4.5 g IV q6h
PLUS anti-MRSA coverage:
- Vancomycin 15 mg/kg IV q12h (maintain trough 10-15 mcg/mL)
- OR Linezolid 600 mg IV q12h
- Goldman-Cecil Medicine, Table 85-10
3. Pneumocystis Pneumonia (PCP) - HIV/Immunocompromised
| Severity | Drug | Dose | Route |
|---|---|---|---|
| Mild (PaO₂ ≥70 mmHg) | TMP-SMX (preferred) | 2 DS tablets (160/800 mg) TID | PO |
| Mild (alternative) | Trimethoprim + Dapsone | 5 mg/kg TID + 100 mg daily | PO |
| Mild (alternative) | Clindamycin + Primaquine | 450-600 mg + 30 mg daily | PO |
| Mild (alternative) | Atovaquone | 750 mg BID with food | PO |
| Moderate-Severe (PaO₂ <70 mmHg) | TMP-SMX IV (preferred) | 5 mg/kg TMP + 25 mg/kg SMX q8h | IV |
| Moderate-Severe (alternative) | Pentamidine | 3-4 mg/kg daily (infuse >60 min) | IV |
| Adjunct (moderate-severe) | Prednisone | 40 mg BID days 1-5; taper over 21 days | PO |
- HIV patients: 21 days total; non-HIV: at least 14 days.
- Goldman-Cecil Medicine, Table 315
4. Tuberculosis Pneumonia
Intensive phase (8 weeks) - RIPE regimen:
- Rifampin (RIF) 10 mg/kg PO daily (max 600 mg)
- Isoniazid (INH) 5 mg/kg PO daily (max 300 mg) + Pyridoxine 25-50 mg to prevent neuropathy
- Pyrazinamide (PZA) 15-25 mg/kg PO daily (max 2 g)
- Ethambutol (EMB) 15-25 mg/kg PO daily
Continuation phase: INH + RIF for 16 more weeks (total 6 months).
5. Newer/Reserve Antibiotics for Pneumonia
These are used for resistant organisms or treatment failures (Fishman's Pulmonary Diseases, Table 125-4):
| Drug | Class | Key Coverage | Notable Side Effects |
|---|---|---|---|
| Omadacycline | Aminocycline | MRSA, DRSP, atypicals | GI effects |
| Lefamulin | Pleuromutilin | MRSA, MSSA, VRE, DRSP, Legionella, Mycoplasma | Hepatotoxicity |
| Delafloxacin | Fluoroquinolone | MRSA, Enterococcus, Legionella, Mycoplasma | Tendon rupture, CNS effects |
| Ceftobiprole | 5th-gen cephalosporin | MSSA, H. influenzae, K. pneumoniae, P. aeruginosa | Hepatotoxicity |
| Telavancin | Lipoglycopeptide | Gram-positives including MRSA and VRE | Renal impairment |
| Nemonoxacin | Non-fluorinated quinolone | Gram-positives, Gram-negatives, MRSA, atypicals | QT prolongation |
Key Principles
- Start early - antibiotics within 4 hours of CAP diagnosis reduces mortality.
- De-escalate - narrow therapy once culture data are available.
- Duration - 5 days is sufficient for most uncomplicated CAP; HAP/VAP generally 7-8 days regardless of pathogen. The ATS 2025 guideline reinforces shorter antibiotic courses.
- Steroids - adjunctive corticosteroids are indicated in severe PCP (PaO₂ <70 mmHg) and in certain severe CAP cases.
- Local resistance patterns matter, especially for Pseudomonas coverage decisions.
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