MIC: 0.015 - 0.06 mg/ml

Tuberculosis is a widespread, infectious disease caused by various mycobacteria strains, usually Mycobacterium tuberculosis. Tuberculosis typically attacks the lungs, but can also affect other parts of the body. Rifapentine is an antibiotic drug used in the treatment of tuberculosis.

In vitro: The activities of rifampin and rifapentine against Mycobacterium tuberculosis residing in human monocytederived macrophages were determined. The MIC and MBC of rifapentine for intracellular bacteria were two- to four-fold lower than those of rifampin. For extracellular bacteria, this difference was less noticeable. [1].

In vivo: Once-a-week exposure to rifapentine concentrations equivalent to that attained in blood after one 600-mg dose resulted during the first week in a dramatic decline in the number of bacteria, and such decline was maintained at a minimal level for a period of four weeks. The prolonged effect of rifapentine found may be associated with high ratios of intracellular accumulation, which were four- to fivefold higher than those found for rifampin [1].

Clinical trial: Rifapentine can be administered twice weekly during the intensive phase of tuberculosis treatment and then once weekly during the continuation phase of treatment. Its efficacy at the approved dosage of 600 mg may be slightly lower than that of rifampin. Studies are needed to determine if equal or greater efficacy could be achieved with higher doses of rifapentine [2].

Reference:
[1] Mor N, Simon B, Mezo N, Heifets L.  Comparison of activities of rifapentine and rifampin against Mycobacterium tuberculosis residing in human macrophages. Antimicrob Agents Chemother. 1995 Sep;39(9):2073-7.
[2] Temple ME, Nahata MC.  Rifapentine: its role in the treatment of tuberculosis. Ann Pharmacother. 1999 Nov;33(11):1203-10.