Background: This study was done to evaluate the efficacy of single bolus administration of Magnesium Sulphate epidurally as an adjuvant to epidural fentanyl citrate for post­operative analgesia with consideration of duration of analgesia and hemodynamic stability after abdominal surgeries and to compare the side effects of both groups. Method: One hundred patients received standard general anaesthesia with epidural anesthesia using 10 ml of 0.5% Bupivacaine. After the surgery, patients were randomized into Group­I [Epidural Fentanyl­ g/ kg in 10 ml saline] and Group­ II [Epidural Magnesium­75 mg along with Fentanyl­1 g/ kg in 10 ml saline]. Supplementary analgesia was provided by Inj. Tramadol­ 50 mg when Verbal Rating Score (VRS) was > 4. Patient’s first analgesic requirement and duration of analgesia were recorded. Results: The duration of analgesia was significantly longer in Group II (290 ± 50 min) as compared to Group­ I (160± 30 min) (P­ 0.001). The frequency of rescue analgesics required in Group­ II (2.1±0.5) was significantly less than that in Group­I (3.3±0.5) (P­ 0.001). VRS was lower in GroupII up to 4 hours postoperatively (P­ 0.001). Conclusion: he Administration of Magnesium­ 75 mg as an adjuvant to Epidural Fentanyl­ 1 g/ kg significantly lowers the Verbal Rating Score (VRS) with prolonged duration of postoperative analgesia as compared with Epidural Fentanyl (1 g/ kg) alone. Concomitant administration of Magnesium also reduces the requirement of breakthrough analgesics without any significant side effects. 

Keywords: Epidural Adjuvants; Fentanyl; Magnesium; Postoperative Analgesia.