Reduced antiviral effect of antiretroviral drugs (eg, rilpivrine, atazanavir, & nelfinavir). Increased toxicity of saquinavir. Increased INR & prothrombin time w/ warfarin. May elevate & prolong serum conc of methotrexate. Potential for increased exposure of digoxin & tacrolimus. Reduced absorption of drugs dependent on gastric pH for absorption (eg, Fe salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole). Decreased exposure w/ strong CYP2C19 or CYP3A4 inducers (eg, St. John's wort, rifampin, ritonavir-containing products). Increased exposure w/ strong CYP2C19 or CYP3A4 inhibitors (eg, voriconazole).