Background & objective: Morphine is a widely used analgesic in management of postoperative pain with well documented analgesic properties and side effects. Tramadol, a new synthetic mu-opioid receptor agonist, little is known about its efficacy and side effects when administered in epidural for pain relief. The aim of this study is to compare the efficacy and side effects of tramadol, morphine versus their combination for postoperative analgesia.
Methods: One hundred and twenty patients undergoing abdominal cancer surgery were assigned to one of three groups randomly, tramadol group (Group T, n = 40), morphine group(Group M, n = 40) and combination of tramadol and morphine group(group T + M, n = 40), for postoperative analgesia. In group T, 12 mg/kg tramadol and 0.125% bupivacaine 100 ml were used for 48 h postoperative analgesia. In group M, 0.12 mg/kg morphine and 0.125% bupivacaine 100 ml; and in group T + M, 6 mg/kg tramadol, 0.12 mg/kg morphine and 0.125%. Bupivacaine 100 ml were used for postoperative analgesia. Efficacy was assessed by comparing visual analogue scale(VAS), Bruggman comfort score (BCS), global satisfaction score (GSS) at several time points over 48 hours. Possile adverse events were recorded.
Results: There is no significant difference among three groups in VAS, but in group T, there are more patients whose VAS > 5 score than those in group M and group T + M. BCS; GSS in group T + M are lower than that in group T and group M. The occurrence rate of nausea and vomiting in group T + M are lower than that in group M.
Conclusions: The efficacy of tramadol in epidural postoperative analgesia is similar to that of morphine, but varied from patient to patient, so the dose of tramadol should be individualized. Combination of tramadol and morphine can provide effective analgesia for postoperative pain and cause little adverse effect, especially reduce the occurrence rate of nausea and vomiting.