Coadministration is not recommended as it decreases tenofovir alafenamide plasma concentrations. Coadministration of carbamazepine (titrated from 100 mg to 300 mg twice a day) with emtricitabine/tenofovir alafenamide (200/25 mg once daily) decreased tenofovir alafenamide AUC and Cmax by 55% and 57%, respectively. However, data from a study with rifampicin suggest that use of tenofovir alafenamide 25 mg once daily with carbamazepine may be acceptable. Coadministration of emtricitabine/tenofovir alafenamide (200/25 mg once daily) and the strong inducer 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). No interaction is expected with emtricitabine.