Opioid-Induced Bowel Dysfunction in Patients Undergoing Spine Surgery: Comparison of Oxycodone and Oxycodone-Naloxone Treatment.

INTRODUCTION: Opioids are needed for postoperative pain in spine surgery patients, but opioid-induced constipation is a harmful adverse event. The aim of this clinical trial was to compare the use of a controlled-release oxycodone-naloxone combination product with oxycodone controlled-release tablets in these patients. The main outcome measure was the prevalence of constipation at 7 days postoperatively assessed with a Bowel Function Index questionnaire. A follow-up assessment at 21 days after surgery was also included.

METHODS: A total of 180 patients undergoing spine surgery, 91 having preoperative opioids in use and 89 opioid-naïve, were randomized to receive twice-daily oxycodone 10 mg or oxycodone-naloxone 10/5 mg controlled-release tablets for the first 7 postoperative days. Patients were followed-up for 21 days after surgery.

RESULTS: At baseline, prevalence of constipation was common both in the opioid-naïve-25/87 (29%) and on-opioid groups 43/90 (48%) (P = 0.009). This increased at 7 days postoperatively with no difference between the groups, 54/89 with oxycodone and 54/88 with oxycodone-naloxone had constipation. At 21 days, constipation was less than in the baseline in both groups, in the opioid-naïve group the prevalence of constipation was 3/43 (7%) in patients with oxycodone-naloxone compared to 9/44 (21%) with oxycodone (effect size 0.68; P = 0.068). Both study compounds provided similar pain relief and were well tolerated.

CONCLUSION: In patients presented for back surgery, the prevalence of constipation was significantly higher than that in the community. In opioid-naïve subjects, oxycodone-naloxone was beneficial concerning constipation; but this was not distinguishable in subjects with chronic opioid use. The analgesic efficacy of oxycodone and oxycodone-naloxone was similar.

TRIAL REGISTRATION: European Clinical Trials Database (EudraCT no. 2012-001816-42) and ClinicalTrials.gov database (Identifier: NCT02573922).