The addition of epidural morphine to ropivacaine improves epidural analgesia after lower abdominal surgery

PURPOSE: To assess the analgesic and side effects of the continuous epidural infusion of 0.2% ropivacaine combined with morphine compared to both drugs alone. METHODS: In this study, both observers and patients were blinded to patient group assignment. Sixty patients scheduled to undergo lower abdominal surgery were enrolled. Patients were randomized to one of three postoperative treatment groups: 1) combination group (a combination of 0.2% ropivacaine and 0.003% morphine); 2) morphine group (0.003% morphine); or 3) ropivacaine group (0.2% ropivacaine). Postoperatively, all solutions were administered epidurally at a rate of 6 mL.hr(-1) for 24 hr. Patients were given iv flurbiprofen as a supplemental analgesic on demand. RESULTS: The combination group showed lower visual analogue scale scores than those of patients receiving either drug alone, both at rest and on coughing. The combination group showed a slight motor block at two hours after the continuous epidural infusion, while the ropivacaine and morphine groups did not show any motor block. The incidence of itching was significantly increased in the morphine and combination groups, compared to the ropivacaine group. There was no significant difference between the numbers of patients with nausea in the three groups. No hypotension or respiratory complications were observed in the three groups. CONCLUSION: The combination of epidural 0.2% ropivacaine and 0.003% morphine has more effective analgesic effects than either of the drugs alone for postoperative pain relief after lower abdominal surgery.