44 ritonavir, ketoconazol, itraconazol, troleandomycin, clarithromycin og nelfinavir) eller moderate CYP3A4- hæmmere (f. eks. amprenavir, aprepitant, diltiazem, erythromycin, fluconazol, fosamprenavir, grapefrugtjuice og verapamil) kan resultere i forhøjede plasmakoncentrationer af fentanyl, hvilket potentielt kan forårsage alvorlige bivirkninger herunder fatal respirationsdepression.
The concomitant use of Effentora with strong CYP3A4 inhibitors (e. g., ritonavir, ketoconazole, itraconazole, troleandomycin, clarithromycin, and nelfinavir) or moderate CYP3A4 inhibitors (e. g., amprenavir, aprepitant, diltiazem, erythromycin, fluconazole, fosamprenavir, grapefruit juice, and verapamil) may result in increased fentanyl plasma concentrations, potentially causing serious adverse drug reactions including fatal respiratory depression.