Objective: To compare postoperative pain in patients undergoing TURP between patient receiving spinal anesthesia with 0.05 mg morphine and 0.5% bupivacaine or spinal bupivacaine alone.
Material and Method: This prospective, randomized, double-blinded study included 80 patients which were randomized into 2 groups. Patients in control group (Group C) received only 0.5% hyperbaric bupivacaine. The other group (Group M) received 0.5% hyperbaric bupivacaine with 0.05 mg morphine. Numerical rating scale (NRS) score was recorded at interval during the first 24 hours postoperative. Time to first analgesics requirement, number of patients who required meperidine, and the total 24-hour meperidine requirement were also recorded. The side effects including respiratory depression, pruritus, nausea and vomiting were also evaluated.
Results: Median maximum NRS score were 3 and 1 in Group C and Group M, respectively which showed no statistically significantly different (p = 0.08). The number of patients who required meperidine, time to first request analgesic requirement and the total 24-hour meperidine requirement were similar between the two groups. Patients in Group M had higher incidence of pruritus, nausea and vomiting. However, only the incidence of pruritus that was statistically significantly different (5.7% vs. 20%, p = 0.04).
Conclusion: This study could not demonstrate the benefit of adding morphine 0.05 mg to spinal anesthesia with 0.5% hyperbaric bupivacaine in patients undergoing TURP.

Keywords: Transurethral resection of prostate, TURP, Spinal morphine, Low dose, Postoperative pain