Which of the following is NOT an antituberculosis agent?

Aspirin is not an antituberculosis agent. The other options—Rifampin, Isoniazid, and Pyrazinamide—are all well-established medications used in the treatment of tuberculosis (TB).

Rifampin works by inhibiting bacterial RNA synthesis, making it effective against Mycobacterium tuberculosis, the bacterium responsible for TB. Isoniazid targets the synthesis of mycolic acids, crucial components of the bacterial cell wall, which also allows it to effectively combat TB infections. Pyrazinamide has a unique mechanism that is effective in acidic environments, which helps to kill dormant bacteria within macrophages.

In contrast, Aspirin is classified as a nonsteroidal anti-inflammatory drug (NSAID) primarily used for pain relief, inflammation reduction, and its anti-platelet effects in cardiovascular conditions. It does not have any efficacy against tuberculosis, which distinguishes it from the antituberculosis agents mentioned. Thus, it is clear why Aspirin is not included as an antituberculosis agent.