Cap: Reduced effects w/ rifampicin & St. John's wort. May increase effects of warfarin or other vit K antagonists, phenytoin, diazepam, digoxin, saquinavir, tacrolimus & cilostazol; increase gastric pH & reduce effects of ampicillin, Fe salts, dasatinib & antifungals eg, ketoconazole & itraconazole; increase effects of both omeprazole & voriconazole; decreased effects of clopidogrel & drugs for HIV treatment eg, atazanavir & nelfinavir. Inj: Delayed elimination, increased blood conc of diazepam, phenytoin & anticoagulants eg, warfarin. Reduced absorption of itraconazole & ketoconazole.