 Medications that should not be taken with efavirenz/emtricitabine/tenofovir include bepridil, midazolam, pimozide, triazolam, or ergot derivatives.Additionally, St. John's wort is known to reduce the effectiveness of efavirenz/emtricitabine/tenofovir, resulting in increased viral load and possible resistance to efavirenz/emtricitabine/tenofovir.Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) of HIV-1.