For a patient with severe ampicillin allergy presenting with pneumonia, which treatment is acceptable?

Levofloxacin is a fluoroquinolone antibiotic that is appropriate for treating pneumonia, especially in patients with a history of severe ampicillin allergy. It is effective against a variety of bacteria, including some strains that may cause community-acquired pneumonia. Levofloxacin can provide broad-spectrum coverage, making it a suitable alternative for someone who cannot receive penicillin derivatives due to an allergy.

In contrast, while ciprofloxacin is also a fluoroquinolone, it is typically less effective against Streptococcus pneumoniae, which is a common pathogen in pneumonia cases. Penicillin VK is a penicillin antibiotic and would not be an acceptable choice for a patient with a severe allergy to ampicillin, as both belong to the same drug class and have similar structures. Nitrofurantoin is primarily used for urinary tract infections and is not effective for pneumonia, making it an unsuitable option in this scenario.

Thus, levofloxacin is recommended as it avoids the risk of allergic reaction while effectively addressing the infection.