Efficacy and Safety of Two Epidural Magnesium Sulfate Regimens for Post-Cesarean Analgesia: A Prospective, Randomized Controlled Trial
Joseph Alejandro Veraza Almeida, Francisco Antonio Tapia ParadaAbstract
Background:
Optimal post-cesarean analgesia is critical for recovery. Magnesium sulfate (MgSO 4 ) is a known neuraxial adjuvant acting as an N-methyl-D-aspartate antagonist, yet the ideal dose balancing efficacy and neonatal safety remains undefined. This trial evaluated two low-dose epidural magnesium regimens.
Materials and Methods:
A prospective, double-blind, randomized controlled trial was conducted with 340 American Society of Anesthesiologists I–II parturients undergoing elective cesarean section. Patients received lidocaine 2% (300 mg) plus fentanyl (100 µg), supplemented with either 75 mg (Group SM75) or 100 mg (Group SM100) of MgSO 4 . Primary outcomes included pain intensity (visual analog scale [VAS] scores) at 2, 4, 8, 12, and 24 h. Secondary outcomes assessed rescue analgesia, block regression, and neonatal well-being (Apgar/resuscitation needs).
Results:
The SM75 group showed significantly lower pain scores at 2, 12, and 24 h compared to SM100 (
Conclusion:
Epidural MgSO 4 at 75 mg provides superior sustained analgesia and a better neonatal safety profile compared to 100 mg of MgSO 4 . Lower neuraxial doses appear to optimize the therapeutic index in obstetric anesthesia.