Mycobacteria are intracellular, have long periods of metabolic inactivity, and tend to develop resistance to any one medication. Therefore, combined medication therapy is used to delay the emergence of resistance. First-line medications, increasingly used together in the treatment of tuberculosis, are isoniazid, ethambutol, rifampin, and pyrazinamide.
See Chapter 9 for a discussion of these medications in pulmonary disease.