From the Guidelines
Azithromycin is generally preferred over amoxicillin for community-acquired pneumonia due to its broader coverage of atypical pathogens. For adults with community-acquired pneumonia, azithromycin is typically prescribed at 500 mg on day 1, followed by 250 mg daily for 4 more days (5 days total) 1. Amoxicillin, while effective against many common bacterial causes of pneumonia, doesn't cover atypical pathogens like Mycoplasma and Legionella. When amoxicillin is used, the typical adult dose is 500-875 mg three times daily for 7-10 days. Azithromycin offers advantages including once-daily dosing, shorter treatment duration, and better coverage of atypical organisms. However, local resistance patterns should be considered, as some regions have increasing pneumococcal resistance to macrolides like azithromycin 2, 3, 4.
Key Considerations
- The choice between azithromycin and amoxicillin should be based on the patient's specific condition, including the presence of comorbidities, recent antibiotic use, and local resistance patterns.
- For patients with penicillin allergies, azithromycin is clearly preferred.
- In more severe cases or with comorbidities, combination therapy or alternative antibiotics might be necessary.
- Patients should complete the full course of either medication even if symptoms improve before finishing treatment.
Treatment Options
- Azithromycin: 500 mg on day 1, followed by 250 mg daily for 4 more days (5 days total)
- Amoxicillin: 500-875 mg three times daily for 7-10 days
- Combination therapy: a β-lactam plus a macrolide or a respiratory fluoroquinolone alone may be used in certain cases 3, 4
Important Notes
- The use of fluoroquinolones to treat ambulatory patients with CAP without comorbid conditions, risk factors for DRSP, or recent antimicrobial use is discouraged due to concern about the development of fluoroquinolone resistance 1.
- Telithromycin, a ketolide antibiotic, is active against S. pneumoniae that is resistant to other antimicrobials commonly used for CAP, but its use is not recommended due to reports of life-threatening hepatotoxicity 1.
From the Research
Comparative Efficacy of Azithromycin and Amoxicillin
- The efficacy of azithromycin versus amoxicillin for the treatment of pneumonia has been studied in several clinical trials 5, 6, 7.
- A study published in the Journal of Chemotherapy found that azithromycin 1g once daily for 3 days was at least as effective as amoxicillin-clavulanate 875/125 mg twice daily for 7 days in the treatment of adult patients with community-acquired pneumonia, with clinical success rates of 92.6% and 93.1%, respectively 5.
- Another study published in the Pediatric Infectious Disease Journal found that azithromycin was as effective as amoxicillin/clavulanate or erythromycin in the treatment of community-acquired pneumonia in children, with clinical success rates of 94.6% and 96.2%, respectively 6.
- A study published in the International Journal of Antimicrobial Agents found that a 3-day course of azithromycin was more effective than 10 days of other antibiotics in the treatment of community-acquired pneumonia, with resolution of pneumonia in 98.4% and 87% of patients, respectively 7.
Bacteriological Efficacy
- The bacteriological efficacy of azithromycin versus amoxicillin has also been studied, with one study finding that azithromycin had a bacteriological success rate of 91.4% compared to 90.9% for amoxicillin-clavulanate 5.
- Another study found that azithromycin had a microbiologic eradication rate of 81% for Chlamydia pneumoniae and 100% for Mycoplasma pneumoniae, compared to 100% and 57%, respectively, for the comparator group 6.
Safety and Tolerability
- The safety and tolerability of azithromycin versus amoxicillin have also been compared, with one study finding that azithromycin had a lower incidence of adverse events (25.0% vs 16.7%) and a lower incidence of treatment-related adverse events (11.3% vs 31%) 5, 6.
- Another study found that azithromycin was well tolerated, with adverse events mainly of a gastrointestinal nature, recorded in 6 patients (7.7%) 8.