Comparison of morphine and sublingual buprenorphine following abdominal surgery.

In a prospective study, patients undergoing abdominal surgery were allocated randomly to receive intermittent morphine 10 mg i.m. (n = 41) or a single injection of buprenorphine 0.3 mg i.m. followed by sublingual buprenorphine 0.4 mg every 6 h (n = 39) for 3 days following operation. Patients receiving buprenorphine were allowed additional morphine, if required. Pain scores (linear analogue scale) in those patients receiving regular sublingual buprenorphine were consistently less than in those receiving intermittent morphine i.m. Half the patients receiving buprenorphine required no additional analgesia; only 15% required additional analgesia after the first day following operation. Arterial blood-gas analyses showed significant hypoxaemia and significantly greater carbon dioxide tensions in those receiving buprenorphine. These results suggest that a regimen based on the use of sublingual buprenorphine provides pain relief comparable to that provided by intermittent opiates i.m.