Clinical evaluation of adding solitary dose of magnesium to fentanyl on post-operative analgesia during combined spinal epidural technique for hip replacement procedures

Deepak Sharma, Daljit Kaur, Bilal Ahmad, Abhishek Kumar, Divya Agarwal


Background: Numerous receptors such as NMDA have evolved in the management of post-operative pain which can be antagonized effectively before the initiation of painful stimuli. The analgesic property of Magnesium is primarily related to the regulation of calcium influx and antagonism of N-methyl-D-aspartate (NMDA) receptors distributed throughout the central nervous system. This study was designed to evaluate if addition of magnesium to epidural fentanyl as pre-emptive solitary dose could prolong post-operative analgesia during combined spinal epidural anesthesia in elective hip replacement surgeries.

Methods: A total of 63 adult consented ASA grade I and II patients aged between 40 and 70 years of either sex, who met the inclusion criteria for hip replacement surgery, were randomized to receive either epidural fentanyl (Group I) or combined epidural magnesium sulphate and fentanyl (Group II). Both the groups subsequently received subarachnoid block with 0.5 % heavy bupivacaine. Intraoperative hemodynamic, subarachnoid block characteristics and 24 hours post-operative analgesia was evaluated.

Results: There was significant delay in two dermatome regression for the combined fentanyl magnesium group (149.07±6.48 min) compared to fentanyl alone group (121.23±2.92 min). The post-operative VAS score was statistically lower for the combined fentanyl magnesium group (lowest:0.7±0.4 at 4th hr, highest: 2.9±0.3 at 20th hr) compared to fentanyl alone group (lowest:1.86±1.7 at 5th hr, highest: 3.37±0.9 at 4th hr). There was highly significant difference in average time to first epidural top up and 24hrs epidural top up consumption between fentanyl alone group (264.83±34.08min, 2.8±0.5) and combined fentanyl magnesium group (398±69.55min, 1.43±0.5). Total epidural top ups were 84 in fentanyl alone group and 43 in combined fentanyl magnesium group. Hemodynamic parameters were stable in both groups.

Conclusions: Pre-emptive co-administration of magnesium sulphate as a solitary dose to epidural fentanyl in CSE technique prolongs the duration of post-operative analgesia, reduce the requirement of epidural top up and provide stable hemodynamic perioperatively compared to epidural fentanyl alone.



Combined spinal epidural(CSE), Fentanyl, Magnesium sulphate

Full Text:



Wakamatsu M, Katoh H, Kondo U, Yamamoto T, Tanaka S. Combined spinal and epidural anaesthesia for orthopaedic surgery in elderly. (Japanese) Masui. 1991;40:1766-9.

Moiniche S, Kehlet H, Dahl JB. A Qualitative and Quantitative Systematic Review of Preemptive Analgesia for Postoperative Pain Relief: The Role of Timing of Analgesia. Anesthesiol. 2002;96:725-41.

Katz J, McCartney CJ. Current status of pre-emptive analgesia. Current Opinion Anesthesiol. 2002;15(4):435-41.

Eliav E, Teich S, Benoliel R, Nahlieli O, Lewkowicz A, Baruchin A, et al. Large myelinated nerve fiber hypersensitivity in oral malignancy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002;94:45-50.

Stubhaug A, Breivik H, Eide P, Kreunen M, Foss A. Mapping of punctuate hyperalgesia around a surgical incision demonstrates that ketamine is a powerful suppressor of central sensitization to pain following surgery. Acta Anaesthesiol Scand. 1997;41:1124-32.

Palmer CM, Cork RC, Hays R, Van Maren G, Alves D. The dose-response relation of intrathecal fentanyl for labor analgesia. Anesthesiology: J Ame Soci Anesthesiolog. 1998;88(2):355-61.

Asokumar B, Newman LM, McCarthy RJ, Ivankovich AD, Tuman KJ. Intrathecal bupivacaine reduces pruritus and prolongs duration of fentanyl analgesia during labor: a prospective, randomized controlled trial. Anesthesia Analgesia. 1998;87(6):1309-15.

Campbell DC, Banner R, Crone LA, Gore-Hickman W, Yip RW. Addition of epinephrine to intrathecal bupivacaine and sufentanil for ambulatory labor analgesia. Anesthesiology: J Ame Soci Anesthesiolog. 1997;86(3):525-31.

Woolf CJ, Thompson SW. The induction and maintenance of central sensitization is dependent on N-methyl-D-aspartic acid receptor activation: Implications for the treatment of post-injury pain and hypersensitivity states. Pain. 1991;44:293-9.

Ascher P, Nowak L. Electrophysiological studies of NMDA receptors. Trends Neurosci. 1987;10:284-8.

Colin JL, McCartney, Joel Katz. A qualitative systemic review of the role of NMDA receptor antagonists in preventive analgesia. Analgesia. 2004;1385-1400.

Tramer MR, Schneider J, Marti RA, Rifat K. Role of magnesium sulphate in postoperative analgesia. Anesthesiol. 1996;84:340-47.

Begon S, Pickering G, Eschalier A, Mazur A, Rayssiguier Y, Dubray C. Role of spinal NMDA receptors, protein kinase C and nitric oxide synthase in the hyperalgesia induced by magnesium deficiency in rats. Brit J Pharmacol. 2001;134(6):1227-36.

Banwait S, Sharma S, Pawar M, Garg R, Sood R. Evaluation of single epidural bolus dose of magnesium as an adjuvant to epidural fentanyl for postoperative analgesia: A prospective randomized double-blind study. Saudi J Anesth. 2012;6:273-8.

Bilir A, Gulec S, Erkan A, Ozkelik. Epidural magnesium reduces postoperative analgesic requirement. British J Anaesthesia. 2007;98:519-23.

Shiva PV, Krishna SS, Singh BD. Comparative study of epidural fentanyl and fentanyl plus magnesium sulphate for postoperative analgesia. J Evidence Based Med Healthcare. 2015;51:8624-30.

Kandil AHA, Hammad RAEA, Shafei MAE, Kabarity RHE, Ozairy HS. Preemptive use of epidural magnesium sulphate to reduce narcotic requirements in orthopedic surgery. Egyptian J Anaesth. 2012;28:17-22.

Shabana Ramadan. Effect of pre-emptive epidural low dose magnesium sulphate on postoperative analgesic requirement after open abdominal hysterectomy. Ain-Shams J Anasthesiol. 2014;7:226-31.