Rifabutin (Rfb) is a bactericidal antibiotic drug primarily used in the treatment of tuberculosis. The drug is a semi-synthetic derivative of rifamycin S. Its effect is based on blocking the DNA-dependent RNA-polymerase of the bacteria. It is effective against Gram-positive and some Gram-negative bacteria, but also against the highly resistant mycobacteria, e.g. ''Mycobacterium tuberculosis'', ''M. leprae'', and ''M. avium intracellulare''.
It is on the World Health Organization's List of Essential Medicines, the most important medication needed in a basic health system.
Rifabutin is now recommended as first-line treatment for tuberculosis, but Rifampicin is more widely used because of its cheaper cost.
Rifabutin is used in the treatment of mycobacterium avium complex disease, a bacterial infection most commonly encountered in late-stage AIDS patients. Its main usefulness lies in the fact that it has lesser drug interactions than rifampicin; therefore HIV infected patients on HAART are usually given rifabutin for treatment of TB.
Rifabutin is well tolerated in patients with HIV-related tuberculosis (TB), but new findings suggest that patients with low CD4 cell counts have a high risk of treatment failure or relapse due to acquired rifamycin resistance. Since patients co-infected with TB and HIV / AIDS are likely to get TB treated first, when the CD4 is suppressed at the time TB treatment begins, doctors and patients should be aware of a possible rifamycin resistance.
Rifabutin is also being investigated in trials for treating Crohn's Disease as part of the anti-MAP therapy. In a Phase 3 study administering sub-therapeutic doses of Rifabutin in combination therapy to patients not identified with MAP infections, it was associated with significant short term benefits.
It has also found to be useful in the treatment of (Chlamydia) Chlamydophila pneumoniae (Cpn) Infection. See external link.
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