Increased prothrombin time w/ warfarin. Increased conc & psychomotor effects of midazolam. Prolonged serum t½
of oral sulfonylureas eg, chlorpropamide, glibenclamide, glipizide & tolbutamide. Increased plasma conc by hydrochlorothiazide. Increased levels of phenytoin, zidovudine. Decreased AUC & shorter t½
w/ rifampicin. Increased conc of cyclosporin. Decreased mean plasma clearance rate of theophylline. Prolonged QTc interval w/ terfenadine. Increased risk of cardiac events w/ cisapride. Increased serum levels of rifabutin, tacrolimus, astemizole & other CYP450-metabolised drugs.