Rifampin is one of the pivotal drugs for the treatment of tuberculosis. The U.S. Food and Drug Administration approved rifampin in 1971 and several trials showed that rifampin-containing regimens were very effective; in combination with pyrazinamide, it became possible to shorten the duration of treatment to 6 months. Virtually all of the studies that support these recommendations used a 10 mg/kg dose of rifampin , but a dose-finding study with an assessment of the maximum tolerated dose was never performed. The recommended dose was chosen on the basis that it was effective at the lowest cost and limited by fear of adverse effects. Boeree and others have performed a studies in patients with tuberculosis to establish the maximum tolerated dose, to assess the incidence and severity of adverse events,to describe the pharmacokinetics, and to measure the bactericidal effect of higher doses of rifampin.