Increased plasma conc w/ PIs eg, indinavir, lopinavir/ritonavir, ritonavir, saquinavir, telaprevir, nelfinavir, boceprevir; azole antifungals eg, ketoconazole, itraconazole, posaconazole, voriconazole; macrolides eg, erythromycin, clarithromycin, telithromycin. Decreased plasma conc w/ dexamethasone, phenytoin, carbamazepine, rifampicin, phenobarb, fosphenytoin, primidone or
Hypericum perforatum (St. John's wort). Increased plasma conc of other CYP3A4-metabolised drugs eg, triazolobenzodiazepines, dihydropyridine Ca-channel blockers, certain HMG-CoA reductase inhibitors ie, statins. Increased risk of bleeding w/ coumarin derivatives eg, warfarin. Decreased plasma exposure to levothyroxine. Increased hepatotoxicity w/ L-asparaginase. CYP3A4 substrates w/ narrow therapeutic window eg, cyclosporine, pimozide, tacrolimus, sirolimus, ergotamine, diergotamine, fentanyl, alfentanil, terfenadine, bortezomib, docetaxel, quinidine); CYP2D6 substrates w/ narrow therapeutic window eg, metoprolol; paracetamol; chemotherapy regimens.