Decreased serum levels w/ rifampicin & St. John's wort. Decreased absorption of ketoconazole, itraconazole & erlotinib. Increased absorption of digoxin. Elevated INR w/ warfarin. Increased C
max & AUC of cilostazol. Increased AUC & prolonged elimination t
½ of cisapride. Increased serum levels of tacrolimus & saquinavir. Decreased serum levels of atazanavir & nelfinavir. Decreased clearance of diazepam w/ oral esomeprazole. Increased MTX levels. May result in more than doubling of esomeprazole exposure w/ voriconazole in patients w/ severe hepatic impairment & prolonged use.