Exacerbated QT prolongation w/ QT prolonging medical products (eg, CV QT prolonging medical products: quinidine, disopyramide, bepridil, sotalol, ibutilide, amiodarone; non-CV QT prolonging medicinal products: pimozide, ziprasidone, sertindole, mefloquine, halofantrine, pentamidine, cisapride, erythromycin IV). Increased risk of arrhythmia w/ K-depleting diuretics (thiazide & loop diuretics). Increased plasma conc w/ CYP3A4 inhibitors [eg, azole antifungals (ketoconazole, itraconazole), macrolide antibiotics (clarithromycin, oral erythromycin, josamycin, telithromycin), HIV PIs (nelfinavir, ritonavir), nefazodone, diltiazem, verapamil, fluconazole]. Increased exposure w/ grapefruit juice. Decreased exposure & activity w/ CYP3A4 inducers [eg, rifampicin, barbiturates, phenytoin,
Hypericum perforatum (St. John's wort)].