A number of recent reports have described the usefulness of the epidural injection of narcotics for the relief of postoperative pain. Morphine, a u-receptor agonist, produce strong analgesic effect with some side effects. Nalbuphine, is a u-antagonist and k-agonist, has an analgesic effect comparable to morphine with little side effects.

We divided 60 patients into 3 groups utilizing the five-day Baxter Infusor in 0.125% bupivacaine at 0.5 ml/hr: 1) Group M (n=20) received initial 2 mg of bolus + 2 mg/day of maintenance morphine 2) Group N(n=20); initial 4 mg of bolus + maintenance 8 mg/day nalbuphine 3) Group M+N(n=20); initial 2 mg morphine of bolus + maintenance 8 mg/day nalbuphine. Analgesic effect was evaluated by visual analogue scale(0-10) at 6, 12, 18, 24 and 48 hour postoperatively. Changes in blood pressure, heart rate, and incidence of side effects were observed.

No significant hemodynamic changes were seen in any of the groups. The patients of group M and M+N get less pain than group N but side-effects of group M were significantly more than group N, M+N.

Nalbuphine hydrochloride could be better agent than morphine in terms of complication and the dose of group M+N (initial morphine 2mg of bolus + maintenance 8 mg/day nalbuphine) may be recommended for postoperative analgesia.