Plasma conc may be increased w/ strong CYP3A4 inhibitors (eg, clarithromycin, telithromycin, troleandomycin, itraconazole, ketoconazole, voriconazole, ritonavir, indinavir, nelfinavir, saquinavir). Plasma conc may be decreased w/ strong CYP3A4 inducers (eg, rifampicin, carbamazepine, phenobarb, phenytoin, St. John's wort). May alter plasma conc of CYP3A4 substrates w/ narrow therapeutic index (eg, midazolam, fentanyl, alfentanil, dihydroergotamine, ergotamine); CYP2C9 sensitive substrates or CYP2C9 substrates w/ narrow therapeutic index (eg, phenytoin, warfarin); substrates of OATP1B, of BCRP or of both (eg, pravastatin, atorvastatin, sulfasalazine, MTX, pitavastatin, rosuvastatin, simvastatin); P-gp substrates w/ narrow therapeutic index (eg, digoxin, dabigatran, colchicine). May have additive effect on QT interval w/ medicinal products w/ known risk of torsades de pointes (eg, bepridil, chloroquine, clarithromycin, halofantrine, haloperidol, methadone, moxifloxacin, pimozide). Decreased bioavailability w/ food.