Comparison of postoperative analgesic effect of intrathecal magnesium and fentanyl added to bupivacaine in patients undergoing lower limb orthopedic surgery

Abstract

Addition of intrathecal magnesium sulfate to spinal anesthesia induced by bupivacaine significantly prolonged the onset of both sensory and motor blockade compared with fentanyl. Although magnesium failed to prolong the time to first analgesic requirement as seen with fentanyl, it reduced the total consumption of opioids in the first 12 hours postoperatively compared with the control group.

Comparative Efficacy of Two Different Dosages of Intrathecal Magnesium Sulphate Supplementation in Subarachnoid Block

“…An inverse relationship has been demonstrated between the severity of pain with different painful medical and surgical conditions and the serum magnesium concentration [25]. Direct intrathecal administration of magnesium has been shown to prolong the action of subarachnoid anaesthesia in animal experiments [27] and in humans [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However magnesium sulphate is currently unlicensed for intrathecal use in the UK.…”

“…Studies have evaluated use of magnesium intrathecally and shown to prolong the action of subarachnoid anaesthesia [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However, most of these studies used an opioid along with magnesium, which could have contributed to the prolongation of blockade after subarachnoid block [6][7][8][9][10][11][12][13], Magnesium alone with LA in a dose of 50 mg and maximum upto 100 mg has been used in a few studies [14][15][16][17][18][19]. Although the results of adding MgSO 4 50 mg to IT bupivacaine are conflicting, the effect of increasing the dose of additional MgSO 4 has not been fully investigated.…”

“…Koining reported that intravenous magnesium administration led to significant reduction in fentanyl consumption in peri and post-operative periods. Studies have evaluated use of magnesium intrathecally and shown to prolong the action of subarachnoid anaesthesia [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However, most of these studies used an opioid along with magnesium, which could have contributed to the prolongation of blockade after subarachnoid block [6-13], Magnesium alone with LA in a dose of 50 mg and maximum upto 100 mg has been used in a few studies [14][15][16][17][18][19].…”

“…Combination with adjuncts [1][2][3][4][5] like epinephrine, clonidine, neostigmine, opioids, midazolam and magnesium [6][7][8][9][10][11][12][13][14][15][16][17][18][19] have been used to prolong analgesia and reduce the incidence of adverse events. These spinal adjuvants allow the use of lower dose of local anaesthetic agents, prolong and intensify the subarachnoid block and offer hemodynamic stability.…”

Intrathecal Midazolam as an Adjuvant in Pregnancy-Induced Hypertensive Patients Undergoing an Elective Caesarean Section: A Clinical Comparative Study

“…However, this procedure has only a limited duration of analgesia and causes maternal hypotension perioperatively, which may be deleterious in PIH patients. The discovery of various spinal receptors like α 2 -adrenergic, cholinergic, opioid, N-methyl-D-aspartate, gamma-aminobutyric acid (GABA), and benzodiazepine receptors triggered the usage of drugs like clonidine, neostigmine, opioids, ketamine, and midazolam for their synergistic effect with hyperbaric bupivacaine (0.5%) in prolonging the duration of analgesia (1,2). In addition, the efficacy of intrathecal amitriptyline and doxepin, which belong to different classes of drugs, have been studied in rats (3).…”