Rifabutin

Rifabutin 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-dependend 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.

History
Scientists at the Italian drug company Achifar discovered rifabutin in 1975. Eventually Archifar became part of Farmitalia Carlo Erba, a unit of the conglomerate Montedison. This company's Adria Laboratories subsidiary filed for Food and Drug Administration (FDA) approval of rifabutin under the brand name Mycobutin&reg; in the early 1990s. The drug gained FDA approval in December 1992.

Other indications
Rifabutin is used in the treatment of mycobacterium avium complex disease, a bacterial infection most commonly encountered in late-stage AIDS patients.

Rifabutin is well tolerated in patients with HIV-related tuberculosis (TB), but patients with low CD4 cell counts have a high risk of treatment failure or relapse due to acquired rifamycin resistance, a new study found.

Since patients co-infected with TB and HIV / AIDS are likely to get TB treated first, doctors and patients should be aware of a possible rifamycin resistance issue, if the CD4 is so suppressed at the time TB treatment is to begin.

Supply
Rifabutin is now sold in the U.S. market by Pfizer.