Ezetimibe: Decreased AUC w/ cholestyramine. Increased AUC w/ ciclosporin. Increased conc w/ fibrates eg, fenofibrate or gemfibrozil. Reports of increased INR when added to anticoagulants eg, warfarin or fluindione. Atorvastatin: Increased plasma conc w/ potent CYP3A4 inhibitors eg, ciclosporin, telithromycin, clarithromycin, delavirdine, stiripentol, ketoconazole, voriconazole, itraconazole, posaconazole, some HCV antivirals (eg, elbasvir/grazoprevir), HIV PIs (eg, ritonavir, lopinavir, atazanavir, indinavir, darunavir); moderate CYP3A4 inhibitors eg, erythromycin, diltiazem, verapamil, fluconazole, amiodarone; BCRP inhibitors eg, elbasvir & grazoprevir. Reduced plasma conc w/ CYP3A4 inducers eg, efavirenz, rifampicin, St. John's wort. Increased systemic exposure w/ transport protein inhibitors eg, ciclosporin; boceprevir. Increased risk of muscle-related events, including myopathy &/or rhabdomyolysis, w/ fibric acid derivatives eg, gemfibrozil; ezetimibe; systemic fusidic acid; colchicine; daptomycin. Lower plasma conc w/ colestipol. Slightly increased conc of digoxin. Increased plasma conc of OCs eg, norethisterone & ethinyl estradiol. Co-administration w/ warfarin caused a small decrease in prothrombin time.