Which of the following medications is NOT a first-line treatment for tuberculosis?

Amoxicillin is not considered a first-line treatment for tuberculosis (TB) because it is a penicillin-type antibiotic primarily used for treating bacterial infections caused by organisms susceptible to penicillin, such as Streptococcus pneumoniae and Staphylococcus aureus, among others. TB, on the other hand, is caused by Mycobacterium tuberculosis, which is resistant to many types of common antibiotics, including amoxicillin.

In contrast, isoniazid, rifampin, and ethambutol are key components of the standard first-line treatment regimen for TB. Isoniazid is effective in inhibiting the synthesis of mycolic acids, which are essential components of the tuberculosis bacterial cell wall. Rifampin works by inhibiting bacterial RNA synthesis, thereby preventing the bacteria from replicating. Ethambutol plays a role in disrupting the formation of the bacterial cell wall. The combination of these medications is critical in effectively treating TB and preventing the development of drug resistance. This makes amoxicillin unsuitable for TB treatment while the other three medications are essential in managing this serious infection.