The role of perioperative IV administration of nimodipine, an L-type calcium channel antagonist which is capable of crossing the blood-brain barrier, on peri-operative opioid and anesthetics requirements, pain intensity, opioid-related side effects and early postoperative bowel mobility in patients undergoing surgical treatment for bowel cancer with open radical colectomy remains scarcely explored. A prospective double-blind, randomized controlled trial investigating the effect of perioperative IV administration of nimodipine in patients undergoing open colectomy for cancer treatment is therefore conducted.