 A significant proportion of patients who undergo surgery take medications on a chronic basis. Little is known about the effects of these medications on the successful conduct of anesthesia and surgery. Diuretics like furosemide may contribute to low blood pressure during surgery, an outcome associated with cardiovascular complications. However, many patients are recommended to take their diuretics on the day of surgery. We wished to determine if preoperative administration of furosemide contributes to intraoperative hypotension compared to placebo. 