April 22, 2009
Mixing the TB antibiotic rifampin with a protease inhibitor combination, ritonavir-boosted atazanavir, could cause hepatotoxicity and gastrointestinal intolerance in TB-HIV co-infected patients, a recent study found. The adverse events occurred when rifampin dosing preceded the PIs in a study.
"Rifampin is the cornerstone of antituberculosis therapy, but induction of hepatic cytochrome P4503A by rifampin markedly lowers HIV protease inhibitor plasma concentrations," noted Dr. David W. Hass of Vanderbilt University School of Medicine and colleagues. "Tuberculosis continues to be important in patients living with HIV worldwide, and research in this area is very important," Haas said.
In the open-label trial, Haas and colleagues studied the interactions and safety of rifampin, ritonavir, and atazanavir among 14 healthy, HIV-negative volunteers. The study included three periods. During period one, participants received 600-mg rifampin every 24 hours for eight days. During the second period, subjects continued the rifampin dosing and added 300-mg atazanavir and 100-mg ritonavir every 12 hours, for at least 11 days. During period three, atazanavir was to be increased to 400 mg every 12 hours.
Reuters Health Medical News