Emtricitabine and Tenofovir alafenamide Atlanta Medicare Drug Interactions

Interaction studies have only been performed in adults.
Emtricitabine and tenofovir alafenamide fumarate should not be administered concomitantly with medicinal products containing tenofovir alafenamide, tenofovir disoproxil, emtricitabine, lamivudine or adefovir dipivoxil.
Emtricitabine: In vitro and clinical pharmacokinetic drug-drug interaction studies have shown that the potential for CYP-mediated interactions involving emtricitabine with other medicinal products is low. Co-administration of emtricitabine with medicinal products that are eliminated by active tubular secretion may increase concentrations of emtricitabine, and/or the co-administered medicinal product. Medicinal products that decrease renal function may increase concentrations of emtricitabine.
Tenofovir alafenamide: Tenofovir alafenamide is transported by P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). Medicinal products that strongly affect P-gp and BCRP activity may lead to changes in tenofovir alafenamide absorption. Medicinal products that induce P-gp activity (e.g., rifampicin, rifabutin, carbamazepine, phenobarbital) are expected to decrease the absorption of tenofovir alafenamide, resulting in decreased plasma concentration of tenofovir alafenamide, which may lead to loss of therapeutic effect of emtricitabine and tenofovir alafenamide fumarate and development of resistance. Co-administration of emtricitabine and tenofovir alafenamide fumarate with other medicinal products that inhibit P-gp and BCRP activity (e.g., cobicistat, ritonavir, ciclosporin) are expected to increase the absorption and plasma concentration of tenofovir alafenamide. Based on data from an in vitro study, co-administration of Emtricitabine and tenofovir alafenamide fumarate and xanthine oxidase inhibitors (e.g., febuxostat) is not expected to increase systemic exposure to tenofovir in vivo.
Tenofovir alafenamide is not an inhibitor of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, or CYP2D6 in vitro. It is not an inhibitor or inducer of CYP3A4 in vivo. Tenofovir alafenamide is a substrate of OATP1B1 and OATP1B3 in vitro. The distribution of tenofovir alafenamide in the body may be affected by the activity of OATP1B1 and OATP1B3.
Other interactions: Tenofovir alafenamide is not an inhibitor of human uridine diphosphate glucuronosyltransferase (UGT) 1A1 in vitro. It is not known whether tenofovir alafenamide is an inhibitor of other UGT enzymes. Emtricitabine did not inhibit the glucuronidation reaction of a non-specific UGT substrate in vitro.
Interactions between the components of emtricitabine and tenofovir alafenamide fumarate and potential co-administered medicinal products are listed in Table 7 (increase is indicated as "↑", decrease as "↓", no change as "↔"). The interactions described are based on studies conducted with emtricitabine and tenofovir alafenamide fumarate, or the components of emtricitabine and tenofovir alafenamide fumarate as individual agents and/or in combination, or are potential drug-drug interactions that may occur with emtricitabine and tenofovir alafenamide fumarate. (See Table 7.)

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