Liverpool HIV Interactions

Potential Interaction

Emtricitabine/Tenofovir alafenamide (FTC/TAF)

Rifapentine

Quality of Evidence: Very Low

Summary:

Coadministration with rifapentine has not been studied. Rifapentine is an inducer and therefore is expected to decrease the exposure of tenofovir alafenamide. Coadministration of emtricitabine/tenofovir alafenamide (200/25 mg twice daily with bictegravir) and rifampicin (600 mg once daily) in healthy volunteers decreased the AUC of tenofovir and tenofovir-DP by ~14% and 24%, respectively, when compared to once daily administration alone. Data from another study with rifampicin suggest that use of tenofovir alafenamide 25 mg once daily with rifapentine may be acceptable. Coadministration of emtricitabine/tenofovir alafenamide (200/25 mg once daily) and rifampicin (600 mg once daily) decreased plasma exposure of tenofovir alafenamide and tenofovir by ~55%. Intracellular tenofovir-DP AUC decreased by 36%, however, intracellular tenofovir-DP exposure was 4.2-fold higher than that achieved with standard dose tenofovir-DF alone (300 mg once daily).

Description:

The co-administration of Descovy is not recommended with rifapentine. Interaction not studied with either of the components of Descovy. Co-administration of rifapentine, a P-gp inducer, may decrease tenofovir alafenamide plasma concentrations, which may result in loss of therapeutic effect and development of resistance.

Descovy Summary of Product Characteristics, Gilead Sciences Ltd, April 2022.

Coadministration is expected to decrease concentrations of tenofovir alafenamide and is not recommended.

Descovy US Prescribing Information, Gilead Sciences Inc, January 2022.

The pharmacokinetics of tenofovir alafenamide and tenofovir diphosphate were determined in healthy volunteers following administration of tenofovir alafenamide alone (25 mg once daily, with emtricitabine) and with rifampicin (600 mg once daily). Rifampicin decreased tenofovir alafenamide AUC and Cmax by 55% and 50%. Plasma tenofovir Cmax, C24 and AUC decreased by 65%, 55% and 54% respectively. Intracellular tenofovir diphosphate (i.e. active entity) concentrations Cmax, C24 and AUC decreased by 38%, 43% and 36%, respectively, but AUC was still 4.21-fold higher than that achieved with standard dose tenofovir-DF alone (300 mg once daily). Rifampicin did not alter emtricitabine pharmacokinetics.

Rifampin effect on intracellular and plasma pharmacokinetics of tenofovir alafenamide. Cerrone M, Alfarisi O, Neary M, et al. J Antimicrob Chemother 2019; 74:1670-8.

The pharmacokinetics of tenofovir alafenamide and tenofovir diphosphate (TDF-DP) were determined following administration of tenofovir alafenamide alone (25 mg once daily, with bictegravir and emtricitabine) or tenofovir alafenamide (25 mg twice daily, with bictegravir and emtricitabine) and rifampicin (600 mg once daily). Following twice daily administration with rifampicin, the plasma AUC of tenofovir alafenamide and its active intracellular metabolite (TFV-DP) were modestly decreased by ~14% and ~24% when compared to tenofovir alafenamide once daily alone. This modest change is not expected to alter the efficacy of tenofovir alafenamide.

Twice daily administration of tenofovir alafenamide in combination with rifampin: potential for tenofovir alafenamide use in HIV-TB coinfection. Custodio JM, et al. 16th European AIDS Conference (EACS). October 2017, Milan, abstract PS13/4.

View all available interactions with Emtricitabine/Tenofovir alafenamide (FTC/TAF) by clicking here.