Background: Prolongation of analgesia in Neuraxial anaesthesia is achieved by adding various adjuvants intrathecally along with local anaesthetic agent. Using two adjuvants together in lower doses will prolong the duration of analgesia without causing much side effects.

Aims: To compare the efficacy and safety of Intrathecal Magnesium v/s Fentanyl with Magnesium sulphate as an adjuvant to 0.5% Bupivacaine in terms of onset and duration of Sensory and Motor Blockade and Duration of Postoperative analgesia.

Material and Methods: Prospective randomized double blinded study was conducted on 70 ASA 1 & 2 patients undergoing elective caesarean section. They were randomly divided into two groups (35 each). All patients received spinal anaesthesia. Group M received 1.7 ml of 0.5% bupivacaine, 0.1 ml (50 mg) magnesium sulphate and 0.2 ml of normal saline intrathecally. Group FM received 1.7 ml of 0.5% bupivacaine, 0.1 ml (50 mg) magnesium sulphate and 0.2 ml (10microgram) of fentanyl intrathecally.

Results: Onset of sensory block was similar in Group M and Group FM. Duration of sensory block was prolonged in group FM (191±45.60) compared to Group M (178.12±38.06). Duration of analgesia was significantly prolonged.

Conclusion: We conclude that, the addition of both intrathecal magnesium sulphate and fentanyl to bupivacaine for spinal anesthesia, in parturients undergoing elective LSCS results in prolonged duration of analgesia.