Comparison of intravenous Magnesium Sulphate with intrathecal Magnesium Sulphate for post- operative analgesia in orthopaedic patients undergoing extracapsular hip fracture surgery

Arvind Kumar, Usha Kumari Chaudhary, Dinesh Kansal, Shelly Rana, Vipin Sharma, Parbeen Kumar


Background: Magnesium sulphate (MgSO4) N methyl D aspartate receptor antagonist has the potential to be an ideal adjuvant for postoperative analgesia via intrathecal or intravenous route. The aim of the study was, we compared the efficacy of two routes of MgSO4 (Intravenous vs intrathecal) as an adjuvant to bupivacaine in subarachnoid block (SAB).

Methods: Ninety, American Society of Anesthesiologists physical status 1 or 2 patients, aged 20-60 years, scheduled for hip surgeries under SAB were recruited in department of Anaesthesia and Dept. of Orthopaedics. Patients in group 1 (n=29) received intrathecal 0.5% (H) bupivacaine 15 mg with 0.1 ml of normal saline and 250 ml 0.9% normal saline intravenous 30 minutes before giving SAB. Group 2 (n=30) patients received intrathecal 0.5% bupivacaine 15mg with 0.1 ml of normal saline and 50mg/kg of magnesium sulphate in 250 ml normal saline intravenous 30minutes before giving SAB. In Group 3 (n=30) patients received intrathecal 0.5% (H) bupivacaine 15 mg with 50mg (0.1ml) magnesium sulphate and 250 ml 0.9% normal saline intravenous 30 minutes before giving SAB. They were evaluated for block characteristics, visual analogue scale at various time intervals up to 24 hours and total rescue analgesic and duration of postoperative analgesia were noted.

Results: Intravenous magnesium sulphate had maximum pain free interval, lower pain scores, longer sensory and motor blockade and less requirement of rescue analgesia as compared to the patients in intrathecal group or control group (P<0.05).

Conclusions: Intravenous magnesium sulphate was more effective as compared to intrathecal route with regards to the pain scores and in providing postoperative analgesia.


Adjuvants, Anesthesia, Analgesia, Magnesium Sulfate, Pain, Postoperative

Full Text:



Kara H, Sahin N, Ulusan V, Aydogdu T. Magnesium infusion reduces perioperative pain. Eur J Anaesthesiol 2002;19:52-6.

Tramer MR, Schneider J, Marti RA, Rifat K. Role of magnesium sulphate in postoperative analgesia.Anesthesiology. 1996;84:340-7.

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

Ryu JH, Kang MH, Park KS, Do SH. Effects of magnesium sulphate on intraoperative anaesthetic requirements and postoperative analgesia in gynaecology patients receiving total intravenous anaesthesia. Br J Anaesth. 2008;100:397-403.

Apan A, Buyukkocak U, Ozcan S, Sari E, Basar H. Postoperative magnesium sulphate infusion reduces analgesic requirements in spinal anaesthesia. EurAnaesthesiol. 2004;21:766-9.

Unlugenc H, Ozalevli M, Gunduz M, Gunasti S, Urunsak IF, Guler T et al. Comparison of intrathecal magnesium, fentanyl, or placebo combined with bupivacaine 0.5% for parturients undergoing elective caesarean delivery. Acta Anaesthesiol Scand. 2009;53:346-53.

Haubold HA, Meltzer SJ. Spinal anaesthesia by magnesium sulphate. J Am Med Assoc. 1906;46:647-50.

Kroin JS, McCarthy RJ, Von Roenn N, Schwab B, Tuman KJ, Ivankovich AD. Magnesium sulphate potentiates morphine antinociception at the spinal level. Anesth Analg. 2000;90:913-7.

Fox C, Ramsoomair D, Carter C. Magnesium: Its proven and potential clinical significance. Southern Medical Journal. 2001;94(12). Available at: view article / 423568

Kiran S. Gupta R, Verma D. Evaluation of a single-dose of intravenous magnesium sulphate for prevention of postoperative pain after inguinal surgery: Indian J Anaesth. 2011;55:31-5.

Albrecht E, Kirkham KR, Liu SS, Bruli R. Peri-operative intravenous administration of magnesium sulphate and postoperative pain: A meta-analysis.Anaesth J Assoc Great Britain and Ireland. 2013;68:79-90.

Buvanendran A, McCarthy RJ, Kroin JS, Leong W, Perry P, Tuman KJ. Intrathecal magnesium prolongs fentanyl analgesia: A prospective, randomized, controlled trial. Anesth Analg. 2002;95:661-6.

Elshanouby NM, Eid HE, Nahla F, Moharram AN. Intra-articular injection of magnesium sulphate and or Bupivacaine for post-operative analgesia after Arthroscopic knee surgery: Anesth and Analg. 2008;106:1548-52.

Samir EM, Badawy SS, Hassan AR. Intrathecal vs intravenous magnesium as an adjuvant to bupivacaine spinal anesthesia for total hip arthroplasty. Egyptian Journal of Anaesthesia. 2013;29(4):395-400.

Kumar M, Dayal N, Rautela RS, Sethi AK. Effect of intravenous magnesium sulphate on post- operative pain following spinal anesthesia. A randomized double blind controlled study. M.E.J. Anesth. 2013;22:251-6.

Gohil K, Bell JR, Ramachandran J, Miljanich GP. Neuroanatomical distribution of receptor for a novel voltage-sensitive calcium channel antagonist.SNX-230(ώ-conopeptide MVIIC). Brain Res. 1994;653:258-66.

Vanegas H, Schaible HG. Effects of antagonists to high threshold Ca channels upon spinal mechanism of pain, hyperalgesia and allodynia. Pain. 2000;85:9-18.

Banihashem N, Hasannasab B, Esmaeili A, Hasannasab B. Addition of intrathecal magnesium sulphate to bupivacaine for spinal anesthesia in cesarean section. Anesth Pain Med. 2015;5:1-4.