The value of epidural magnesium sulfate as an adjuvant to bupivacaine and fentanyl for labor analgesia

Objective: We conducted this clinical study to assess the adjuvant effects of single dose magnesium sulfate (Mg) when administered epidurally during labor with fentanyl and bupivacaine. Methods: Eighty healthy nulliparous women in labor requesting epidural analgesia were divided into two groups. Group 1 received bupivacaine 0.125% with magnesium sulfate 50 mg and fentanyl 50 μg as a loading dose; group 2, received bupivacaine 0.125% and fentanyl 50 μg only. Hemodynamic parameters, motor and sensory evaluation, cervical dilation at time of consenting, the progress of labor, the visual analog pain score (VAS), Apgar score, cord blood acid base status, side effects as nausea, vomiting, itching and respiratory depression were recorded. Fetal heart rate tracings were also documented. Results: Epidural single dose magnesium sulfate added to bupivacaine and fentanyl in labor resulted in significantly faster onset and longer duration of epidural analgesia (169 ± 50 min) in comparison to those patients who received bupivacaine and fentanyl only (105 ± 41 min), also there was a significant reduction in the number of women requiring additional boluses of bupivacaine when Mg was added (P = 0.016). The two groups had no significant differences as regards maternal satisfaction score, maternal and neonatal adverse effects. Conclusion: Magnesium sulfate added to bupivacaine and fentanyl for labor epidural analgesia resulted in faster onset, longer duration of action and reduced the break through pain.