Co-admistration of Atorvastatin with clarithrmycin, erythromycin, itracanazole, protease inhibitors, diltiazem, verapamil, amlodipine, amiodarone or grape juice can result in increase in Atorvastatin concentration. Efavirenz and rifampin can reduce the Atorvastatin plasma concentrations. Atorvastatin can increase the plasma concentration of digoxin, norethisterone and ethinyl oestradiol. The risk of myopathy may increase with concomitant use of ezetimibe or fibrates and Atorvastatin.