No pharmaceutical opinion available for this interaction.
Rifampin increases the metabolism (CYP 3A4) and decreases the plasma concentration of Darunavir / ritonavir.
2C9, 2C19, 2C8 (moderate), UGT (moderate)
3A4 (strong), 2D6 (moderate), 2B6 (probable)
Possible decrease of clinical efficacy.
Risk of a possible development of resistance to antiretroviral class.
1A2, 2C9, 2E1, P-gp
1A2, 2C9, 2C19, 3A4-7, UGT 1A1, P-gp
Increased risk of hepatotoxicity.
Use an alternative.
Rifabutin either 150 mg QD, every 2 days or 3 times a week (see rifabutin with PIs) or choose an antibiotic that does not interact with PIs.
Co-administration of rifampicin 600 mg QD with protease inhibitors such as lopinavir/ritonavir, darunavir/ritonavir, atazanavir/ritonavir and atazanavir alone causes a decrease in AUC and Cmin of approximately 75% to 80%.
Ref #3571 : This study evaluated the safety and pharmacokinetic profile of adjusted doses of darunavir/ritonavir (1600/200 mg QD and 800/100 mg BID) with rifampicin in virologically suppressed PLWH without TB. The study was stopped early because adjusted doses of darunavir/ritonavir with rifampicin had unacceptable risk of hepatotoxicity. Darunavir trough concentrations were markedly reduced with the daily adjusted dose.
Ref #3425 : This In vitro inhibition study investigates the complex interplay between CYP3A induction, inhibition, metabolism and hepatic transport using the HepatopacTM system which displays a singular capacity in capturing all relevant pathways. Addition of 600 mg rifampicin resulted in a pronounced decrease of darunavir Cmax, AUC24h, and Ctrough in the various simulated regimens (800/100 mg QD DRV/r, 1600/200 mg QD DRV/r and 800/100 mg BID DRV/r). Based on their findings, changing the darunavir/ritonavir regimen from 800/100 mg QD to 800/100 mg BID was identified as the most promising regimen to counter the interaction of 600 mg QD rifampicin in HIV patients co-infected with TB.
Ref #3116 : To increase the chance of achieving therapeutic serum levels and reduce the development of resistance and treatment failures some experts, as well as the CDC, recommend a 150mg QD dose. See rifabutin + PIs.