Emtricitabine and tenofovir-DF used as PrEP are not expected to be coadministered with antiretrovirals. In addition, emtricitabine/tenofovir-DF should not be coadministered with other products containing emtricitabine, lamivudine, tenofovir alafenamide or tenofovir-DF. Emtricitabine and tenofovir-DF are unlikely to affect the exposure of antiretroviral drugs initiated after discontinuation of emtricitabine and tenofovir-DF for PrEP.

Descovy contains tenofovir alafenamide and therefore should not be administered with tenofovir-DF.

Emtricitabine and tenofovir-DF used as PrEP are not expected to be coadministered with antiretrovirals. Emtricitabine and tenofovir-DF are unlikely to affect the exposure of antiretroviral drugs initiated after discontinuation of emtricitabine and tenofovir-DF for PrEP.

Emtricitabine and tenofovir-DF used as PrEP are not expected to be coadministered with antiretrovirals. In addition, emtricitabine/tenofovir-DF should not be coadministered with other products containing emtricitabine, lamivudine, tenofovir alafenamide or tenofovir-DF. Emtricitabine and tenofovir-DF are unlikely to affect the exposure of antiretroviral drugs initiated after discontinuation of emtricitabine and tenofovir-DF for PrEP.

Coadministration has not been studied and is not recommended in the product labels for Descovy. St John’s wort, a P-gp inducer, may decrease tenofovir alafenamide plasma concentrations. However, a recent study suggests a low risk of a clinically relevant pharmacokinetic interaction with low-hyperforin formulations (<1 mg/day) of St John’s Wort (hyperforin is the constituent responsible for induction of CYPs and P-gp). Coadministration may be considered with St John’s Wort formulations that clearly state the hyperforin content and which have a total daily hyperforin dose of 1 mg or less. In addition, data from a study with rifampicin suggest that use of tenofovir alafenamide 25 mg once daily with primidone 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.

Coadministration has not been studied. No effect is expected on emtricitabine, however, the effect on tenofovir alafenamide is unclear as curcumin and/or turmeric extracts appeared to inhibit P-gp in vitro, but a contradictory effect was observed in vivo. No a priori dose adjustment is recommended.

Coadministration has not been studied. The effect on tenofovir-DF is unclear as curcumin and/or turmeric extracts appeared to inhibit P-gp in vitro, but a contradictory effect was observed in vivo. No a priori dose adjustment is recommended.

Coadministration has not been studied. No effect is expected on emtricitabine, however, the effect on tenofovir-DF is unclear as curcumin and/or turmeric extracts appeared to inhibit P-gp in vitro, but a contradictory effect was observed in vivo. No a priori dose adjustment is recommended.

No clinically significant pharmacokinetic interaction was observed between tenofovir-DF and dolutegravir. Coadministration of tenofovir-DF (300 mg once daily) and dolutegravir (50 mg once daily) decreased dolutegravir Cmax and Ctrough by 3% and 8%, and increased AUC by 1%. Tenofovir Cmax, AUC and Ctrough increased by 9%, 12% and 19%, respectively. No dosage adjustment is necessary.

Coadministration of dolutegravir (50 mg once daily) with emtricitabine/tenofovir alafenamide (200/10 mg, once daily) increased tenofovir AUC and Cmax by 25% and 10% (n=10). No significant effects were observed on dolutegravir pharmacokinetics relative to historical controls. Coadministration of dolutegravir (50 mg once daily) and tenofovir alafenamide/emtricitabine/elvitegravir/cobicistat (10/200/150/150 mg) had no significant effect on the pharmacokinetics of dolutegravir and tenofovir alafenamide. The recommended dose of Descovy for HIV-1 treatment is 200/25 mg once daily.

Coadministration has not been studied. St John’s Wort, an inducer of P-gp, could reduce the absorption of tenofovir-DF. However, based on the results of the interaction study between tenofovir-DF and rifampicin (another inducer of P-gp), St John’s Wort would be expected to cause only a small decrease in tenofovir-DF.  

Coadministration has not been studied. Based on metabolism and clearance a clinically significant interaction with emtricitabine is unlikely. St John’s Wort, an inducer of P-gp, could reduce the absorption of tenofovir-DF. However, based on the results of the interaction study between tenofovir-DF and rifampicin (another inducer of P-gp), St John’s Wort would be expected to cause only a small decrease in tenofovir-DF.