Elvitegravir cobicistat emtricitabine tenofovir drug interactions

# Drug Interactions

## Other Antiretroviral Medications
STRIBILD is a complete regimen for the treatment of HIV-1 infection; therefore, STRIBILD should not be administered with other antiretroviral medications for treatment of HIV-1 infection. Complete information regarding potential drug-drug interactions with other antiretroviral medications is not provided.

## Potential for STRIBILD to Affect Other Drugs
Cobicistat, a component of STRIBILD, is an inhibitor of CYP3A and CYP2D6 and an inhibitor of the following transporters: p-glycoprotein (P-gp), BCRP, OATP1B1 and OATP1B3. Thus, coadministration of STRIBILD with drugs that are primarily metabolized by CYP3A or CYP2D6, or are substrates of P-gp, BCRP, OATP1B1 or OATP1B3 may result in increased plasma concentrations of such drugs. Elvitegravir is a modest inducer of CYP2C9 and may decrease the plasma concentrations of CYP2C9 substrates.

## Potential for Other Drugs to Affect One or More Components of STRIBILD
Elvitegravir and cobicistat, components of STRIBILD, are metabolized by CYP3A. Cobicistat is also metabolized, to a minor extent, by CYP2D6.
Drugs that induce CYP3A activity are expected to increase the clearance of elvitegravir and cobicistat, resulting in decreased plasma concentration of cobicistat and elvitegravir, which may lead to loss of therapeutic effect of STRIBILD and development of resistance .
Coadministration of STRIBILD with other drugs that inhibit CYP3A may decrease the clearance and increase the plasma concentration of cobicistat .

## Drugs Affecting Renal Function
Because emtricitabine and tenofovir, components of STRIBILD are primarily excreted by the kidneys by a combination of glomerular filtration and active tubular secretion, coadministration of STRIBILD with drugs that reduce renal function or compete for active tubular secretion may increase concentrations of emtricitabine, tenofovir, and other renally eliminated drugs and this may increase the risk of adverse reactions. Some examples of drugs that are eliminated by active tubular secretion include, but are not limited to acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g. gentamicin), and high-dose or multiple NSAIDs .

## Established and Other Potentially Significant Interactions
Table 6 provides a listing of established or potentially clinically significant drug interactions. The drug interactions described are based on studies conducted with either STRIBILD, the components of STRIBILD, (elvitegravir, cobicistat, emtricitabine, and tenofovir DF) as individual agents and/or in combination, or are predicted drug interactions that may occur with STRIBILD . The table includes potentially significant interactions but is not all inclusive.

## Drugs without Clinically Significant Interactions with STRIBILD
Based on drug interaction studies conducted with the components of STRIBILD, no clinically significant drug interactions have been either observed or are expected when STRIBILD is combined with the following drugs: entecavir, famciclovir, H2 receptor antagonists, methadone, proton pump inhibitors and ribavirin.