Rosh Internal Medicine Boost Practice Exam

Which drug is classified as a first-line treatment for community-acquired pneumonia without risk factors for resistant organisms?

1. Amoxicillin

2. Azithromycin

3. Levofloxacin

4. Clarithromycin

The correct answer is: Amoxicillin

Amoxicillin is considered a first-line treatment for community-acquired pneumonia (CAP) in patients who do not have risk factors for resistant organisms. This choice is supported by its effectiveness against common bacterial pathogens that cause pneumonia, such as Streptococcus pneumoniae. Amoxicillin is a beta-lactam antibiotic that works by inhibiting cell wall synthesis in bacteria, leading to cell lysis and death. In cases of uncomplicated CAP where the risk for antibiotic resistance is low, amoxicillin provides an adequate coverage profile and good safety profile, making it a reliable option for initial therapy. The guidelines typically recommend using amoxicillin in otherwise healthy adults without significant comorbidities or previous antibiotic use in the last three months, thus aligning with the treatment strategy for this scenario. The other medications listed serve different roles or are reserved for specific cases. Azithromycin and clarithromycin are macrolides, which might be used for patients with atypical pneumonia or those who have specific risk factors. Levofloxacin, a fluoroquinolone, is generally reserved for more complicated cases or when there is a concern for resistant pathogens due to its broader spectrum of activity and potential for side effects. Therefore, in the context presented, amoxicillin