ABSTRACT
Background: Subarachnoid block achieved a wide spread popularity as a simple and effective method of
anesthesia for elective cesarean sections.The use of intrathecal adjuvants has gained popularity, with the
intention of reducing the dose of local anesthetics, maintaining hemodynamic stability and delaying the onset of
pain during the postoperative period The present study compared between fentanyl and magnesium sulphate as
adjuvant to hyperbaric bupivcaine in subarachnoid block for patients undergoing elective cesarean sections.
Subject and Methods: A total of 56 consented pregnant females undergoing elective cesarean sections, ASA
grade I and II, were randomized into two groups of 28 patients
each. Group F received 12.5 mg of intrathecal 0.5% hyperbaric bupivacaine ( 2.5 ml ) + 12.5 μg (0.25 mL)
fentanyl + .75 ml normal saline, Group M 12.5 mg of intrathecal 0.5% hyperbaric bupivacaine ( 2.5 ml ) + 100
mg (1 ml) magnesium sulfate. The two groups were assessed for character of the block, haemodynamic changes,
duration of post operative analgesia, the side effects.
Results: The onset of both sensory and motor block was slower in the magnesium group. The duration of spinal
anesthesia and motor block were significantly longer in the magnesium group. Total analgesic dose
requirement was less in Group M. Hemodynamic parameters were comparable in the two groups. Intrathecal
magnesium caused minimal side effects.
Conclusion: The addition of magnesium sulfate 100 mg to bupivacaine for sub-arachnoid block in patients
undergoing elective cesarean section prolongs the duration of analgesia and reduces postoperative analgesic
requirements without additional side effects and adverse neonatal outcomes.