The best antibiotic to treat pneumonia depends on the type of pneumonia, patient factors, and local resistance patterns. For community-acquired bacterial pneumonia (CAP) in otherwise healthy adults without comorbidities, the first-line antibiotics commonly recommended are:
- Amoxicillin (a penicillin-class antibiotic), typically 1 gram three times daily, effective against common pathogens like Streptococcus pneumoniae and Haemophilus influenzae.
- Macrolides such as azithromycin (500 mg on day 1, then 250 mg daily for 4 days) or clarithromycin , which cover typical and atypical pathogens including Mycoplasma pneumoniae and Legionella pneumophila.
- Doxycycline (100 mg twice daily) is an alternative, especially for those allergic to penicillins or macrolides
For patients with comorbidities or risk factors for drug-resistant S. pneumoniae , treatment usually involves:
- A combination of a beta-lactam (e.g., amoxicillin/clavulanate or cefuroxime) plus a macrolide or doxycycline.
- Alternatively, respiratory fluoroquinolones such as levofloxacin can be used, especially if macrolides or beta-lactams are contraindicated
In severe cases or hospitalized patients, intravenous antibiotics like ceftriaxone combined with a macrolide or fluoroquinolone are recommended
. Recent meta-analyses suggest quinolones (e.g., levofloxacin) and macrolides (e.g., azithromycin) are associated with better clinical response and lower mortality, though no single antibiotic is conclusively superior
. Summary:
Patient Type| Recommended Antibiotics
---|---
Healthy outpatient (no comorbidities)| Amoxicillin OR Azithromycin OR
Doxycycline
Outpatient with comorbidities| Beta-lactam (e.g., amoxicillin/clavulanate) +
macrolide OR respiratory fluoroquinolone (e.g., levofloxacin)
Hospitalized (non-severe)| IV beta-lactam (e.g., ceftriaxone) + macrolide OR
fluoroquinolone alone
Severe pneumonia| Combination therapy with beta-lactam + macrolide or
fluoroquinolone
Treatment duration is generally at least 5 days, continuing until clinical stability is achieved
. In conclusion, azithromycin is often the initial drug of choice for uncomplicated pneumonia, while amoxicillin is commonly used especially in children and penicillin-tolerant adults. For more complicated cases, combination therapy or fluoroquinolones are preferred
