COMPARISON OF INTRAVENOUS MAGNESIUM AND PLACEBO ADMINISTRATION ON POSTOPERATIVE PAIN AND ANALGESIC CONSUMPTION DURING SPINAL ANESTHESIA FOR INGUINAL HERNIA REPAIR

Previous studies have suggested that magnesium may be a useful adjuvant to postoperative analgesia. We investigated efficacy of intravenous infusion of magnesium sulfate during spinal anesthesia to reduce post-operative pain and opioid consumption in patients undergoing inguinal hernia surgery.We randomly divided one hundred patients’ age 18-55 years old and ASA class I-II undergoing inguinal surgery into two groups. The magnesium group (Group M) received magnesium sulfate 50 mg/kg in 100 ml normal saline intravenously within 10 minutes and 15 mg/kg/h by continuous infusion during the operation in one hour. The control group (Group S) received the same amount of normal saline without magnesium sulfate. All patients received spinal anesthesia. Postoperative pain scores, meperidine consumption, and motor block were evaluated during 24 hours after surgery.Postoperative pain scores were significantly lower in Group M at 2, 3, 4 and 6 hours after surgery (P<0.05). Motor block was longer in Group M (P<0.05). Cumulative postoperative meperidine consumptions were also significantly lower in Group M at 24 h after surgery (P<0.05). 12% nausea and 26% flashing have been reported in Group M. A bolus and intravenous infusion of magnesium sulfate administration during spinal anesthesia improves postoperative analgesia. IRCT201201088645N1