A Comparison of Targinact vs. Oxycodone on Gut Function After Colorectal Surgery

Two key requirements for discharge from hospital after major abdominal surgery are adequate oral analgesia and resumption of oral nutrition. Up to 40% of patients suffer delayed discharge after abdominal surgery due to delayed return of gut function, manifesting as nausea, vomiting, constipation and abdominal distension. Opiates and their derivatives are the mainstay of postoperative analgesic regimens after abdominal surgery and are highly effective in achieving adequate pain control. However, opioids cause impaired gut function by reducing normal forward propulsion and increasing gut spasm. Opioid receptor blockers such as Alvimopan counteract these effects and can accelerate postoperative gut recovery but are expensive and cause cardiac complications; alternative painkillers such as non-steroidal anti-inflammatories are less effective than opioids and have been linked with increased risk of anastomotic leaks. Targinact is a combination of prolonged release opioid analgesic (oxycodone hydrochloride) and naloxone hydrochloride (an opioid receptor blocker). The formulation of the product confines the naloxone action to the gut to reduce the unwanted side-effects on gut function. Targinact has been shown in patients with chronic severe pain to provide comparable analgesia to other opioid analgesics whilst reducing the unwanted side-effect of constipation. The Investigators wish to test the hypothesis that Targinact will provide adequate analgesia after colonic resection with reduced postoperative gastrointestinal dysfunction. The surgical procedure chosen to test this hypothesis is laparoscopic segmental colectomy, a consistently reproducible intervention with a postoperative gut dysfunction rate of up to 40% (prospective data from the Edinburgh Colorectal Unit). The main outcome of the study will be return of normal gut function at the time of planned discharge (Day 3).