Which one of the following antimicrobial drugs is suitable for treatment of both tuberculosis and leprosy ?

Rifampicin is active against both Mycobacterium tuberculosis and Mycobacterium leprae, making it a core agent used in standard first-line antituberculosis regimens and in multidrug therapy (MDT) for leprosy. Clinical and pharmacologic sources state rifampin/rifampicin is the single most bactericidal agent for M. leprae and must be combined with other antileprosy drugs to prevent resistance [1]. For tuberculosis, rifampicin is listed among the primary first-line antitubercular drugs (alongside isoniazid, ethambutol, and pyrazinamide) and is essential in short-course chemotherapy for drug-susceptible TB. Other options listed (isoniazid, p-aminosalicylic acid, streptomycin) are not routinely used as standard shared agents for both diseases in contemporary regimens.

Sources

1. [1] https://tmedweb.tulane.edu/pharmwiki/doku.php/all_antimycobacterials