Inhibited metabolism of substrates prolonging QT interval eg, astemizole, bepridil, cisapride, dofetilide, halofantrine, mizolastine, pimozide, quinidine, sertindole, terfenafine; ergot alkaloids; HMG-CoA reductase inhibitors eg, simvastatin, lovastatin; triazolam, oral midazolam; warfarin. Increased or prolonged therapeutic outcome &/or adverse effects w/ oral hypoglycemics eg, sulphonylureas; phenytoin; HIV PIs eg, saquinavir; antineoplastic agents eg, vinca alkaloids, busulfan, docetaxel; Ca-channel blockers eg, dihydropyridines, verapamil; immunosuppresive agents eg, cyclosporine, tacrolimus, sirolimus; alfentanil, alprazolam, brotizolam, buspirone, carbamazepine, cilostasol, disopyramide, ebastine, methylprednisolone, midazolam IV, reboxetine, rifabutin, sildenafil, trimetrexate.