Not recommended in concurrent use w/ γ-aminobutyric acid-potentiating activity eg, barbiturates, benzodiazepines, Na oxybate, valproic acid. May potentiate activity of benzodiazepines. Concomitant use w/ P-gp inhibitors (eg, amiodarone, carvedilol, clarithromycin, cyclosporine, erythromycin, itraconazole, ketoconazole, quinidine, ritonavir, tamoxifen, verapamil) or inducers (eg, amprenavir, clotrimazole, phenothiazines, rifampin, ritonavir, St. John's wort). Elevated INR w/ warfarin.