ABSTRACT
BACKGROUND: Recent studies suggest that preoperative block of the N-Methyl-D-Aspartate (NMDA) receptor with NMDA antagonists may reduce postoperative pain. We infused magnesium sulfate, anatural NMDA receptor antagonist, preoperatively to evaluate the preemptive analgesic effect of magnesium. METHODS: Sixty healthy patients who underwent total abdominal hysterectomy under general sthesia were randomly divided into three groups. Group 1 was the control group, while Groups 2 and 3 received intravenous magnesium (Group 2 : 0.1 mg/kg bolus, 0.015 mg/kg/hr for 6hr, Group 3 : 0.2 mg/kg bolus, 0.03 mg/kg/hr for 6hr). Postoperative pain scorers (Visual Analog Scale: VAS and Prince Henry Score: PHS) and the amount of analgesic consumption were evaluated at 6, 24, 48 and 72 hours by a double blind manner. RESULTS: The patients in Group 3 had lower pain scores at 6 and 24 hours compared to those in Group 1, but there were no significant differences in PHS and cumulative amounts of analgesic consumption among the three groups. CONCLUSIONS: The preoperative administration of intravenous magnesium reduced postoperative pain scores. However, further study is needed before its clinical use for postoperative analgesic purposes.