Updates By Carol A. Kemper, MD, FACP

Update on Rifamycins in HIV and TB

Source: MMWR Morb Mortal Wkly Rep 2000;49:185-189.

Patients concurrently infected with HIV and tuberculosis (TB) present complex care issues for clinicians, not the least of which are the selection of an optimal regimen for both diseases and the management of drug interactions. Earlier guidelines recommended against the use of rifampin in patients receiving protease inhibitors or the use of rifabutin in any patient receiving ritonavir or delavirdine.

Based on newer pharmacological data, the March 10 issue of MMWR presents newly modified recommendations for the use of rifamycins in HIV-infected patients. Rifampin can be used for the treatment of active TB in patients receiving an efavirenz- or ritonavir-containing regimen, or in patients receiving the combination of ritonavir and saquinavir. Rifabutin can be used in patients receiving efavirenz or ritonavir, but the dose should be increased to either 450 mg or 600 mg daily with the former agent and decreased substantially to 150 mg two or three times weekly with the latter. The dose of rifabutin does not require modification if used with saquinavir (soft gel) as a single agent.

The use of the rifamycins in patients receiving other antiretroviral regimens remains uncertain, but patients with active TB should generally receive a rifamycin-containing regimen whenever possible, even at the expense of more potent antiretroviral therapy. Should this not be possible, an antituberculous regimen containing no rifamycin can be considered. The MMWR also stated that the management of these patients requires the active input of a physician with expertise in the management of both of these diseases.