Background and objective: Magnesium has antinociceptive effects in animal and human models of pain. These effects are primarily based on the regulation of calcium influx into the cell. The aim of this study was to determine whether perioperative infusion of magnesium would reduce postoperative pain and anxiety.

Methods: Twenty-four patients, undergoing elective hysterectomy, received a bolus of 30 mg kg−1 magnesium sulphate or the same volume of isotonic sodium chloride solution intravenously before the start of surgery and 0.5 g h−1 infusion for the next 20 h. Intraoperative and postoperative analgesia were achieved with fentanyl and morphine respectively. Patients were evaluated pre- and postoperatively for anxiety.

Results: Fentanyl consumption and total morphine requirements were significantly decreased in the magnesium group compared to the control group. Postoperative anxiety scores and sedation were similar between groups.

Conclusions: Continuous magnesium infusion, including the pre-, intra-, and postoperative periods reduces analgesic requirements. These results demonstrate that magnesium can be an adjuvant for perioperative analgesic management.