Risk of myopathy increased w/ concurrent administration of cyclosporine, fibric acid derivatives, erythromycin, niacin or azole antifungals. Decreased atorvastatin plasma conc w/ oral antacid susp containing Mg & Al hydroxides, colestipol, efavirenz & rifampin. Increases steady-state plasma digoxin conc. Increased atorvastatin plasma conc w/ erythromycin, protease inhibitors, diltiazem HCl & grapefruit juice. Increases AUC values for norethindrone & ethinylestradiol.