Magnesium sulfate reduces postoperative pain in women with cesarean section: A meta‐analysis of randomized controlled trials

Abstract

Objectives: The use of magnesium sulfate (MgSO 4 ) as an adjunct in different anesthetic regimens for cesarean section (CS) delivery often reports conflicting results.This study aimed to review the effectiveness of MgSO 4 on improving postoperative analgesia after CS systematically. Methods: PubMed, Embase, and the Cochrane library were searched for randomized controlled trials (RCTs) published from inception to February 2020. Results: A total of 880 women were included (440 in each group). MgSO 4 had a statistically significant effect compared to the control group on the highest VAS (weighted mean difference [WMD] = −0.74, 95% confidence interval [CI] = −1.03 to −0.46, p < 0.001, I 2 = 91.7%, p heterogeneity < 0.001) and the last VAS (WMD = −0.47, 95% CI = −0.71 to −0.23, p < 0.001, I 2 = 95.0%, p heterogeneity < 0.001). MgSO 4 prolonged the time to the first use of analgesia compared to the control group (standardized mean difference [SMD] = −3.03 min, 95% CI = −4.32 to −1.74, p < 0.001, I 2 = 96.3%, p heterogeneity < 0.001). MgSO 4 decreased the consumption of analgesia compared to the control group (SMD = −3.20 mg of IV morphine equivalent, 95% CI: −5.45 to −0.95, p = 0.005, I 2 = 97.6%, p heterogeneity < 0.001).Discussion: MgSO 4 decreases the highest VAS in women who underwent general anesthesia, spinal anesthesia, or epidural for CS (all p < 0.05). Additional MgSO 4 significantly reduces postoperative pain in women undergoing CS.

Perioperative Magnesium for Postoperative Analgesia: An Umbrella Review of Systematic Reviews and Updated Meta-Analysis of Randomized Controlled Trials

“…The study selection process and reasons for exclusion are showed in Figure 1. Participants were pregnant women in two studies [16,17], pediatric patients in three [18][19][20], and adult patients in the others. Magnesium as an adjuvant was administered pre-and/or intraoperatively in the intervention group, while placebo or nothing in comparison with magnesium was administered in the control group.…”

“…Sixteen included studies were systematic reviews and meta-analyses of RCTs, while one study was a systematic review of RCTs [21]. Routes of magnesium administration were intravenous in seven studies [21][22][23][24][25][26][27], intrathecal and/or epidural in five [16,17,[28][29][30], and intra-articular in two [31,32]. There were several routes, including intravenous, intrathecal, epidural, and local approaches, in three studies [17,18,20].…”

“…Routes of magnesium administration were intravenous in seven studies [21][22][23][24][25][26][27], intrathecal and/or epidural in five [16,17,[28][29][30], and intra-articular in two [31,32]. There were several routes, including intravenous, intrathecal, epidural, and local approaches, in three studies [17,18,20]. The types of surgery were cesarean section in two studies [16,17], tonsillectomy in two [18,20], arthroscopic surgery in two [31,32], and laparoscopic cholecystectomy in one [23].…”

“…There were several routes, including intravenous, intrathecal, epidural, and local approaches, in three studies [17,18,20]. The types of surgery were cesarean section in two studies [16,17], tonsillectomy in two [18,20], arthroscopic surgery in two [31,32], and laparoscopic cholecystectomy in one [23]. The remaining patients underwent multiple surgical procedures.…”

“…Pain-related outcomes were pain score, analgesic consumption, time to first analgesic request, and number of patients requiring rescue analgesics after surgery. Ten studies in adult patients [16,17,[22][23][24][25][26][27]31,32] and two studies in pediatric patients [18,20] conducted a meta-analysis regarding pain score after surgery. The majority of studies described using magnesium as part of a multimodal analgesic regimen to reduce postoperative pain intensity within 24 h of surgery.…”