Different additives have been used to prolong spinal anesthesia. We designed a prospective, randomized, double-blind study to evaluate the effect of spinal anesthesia. Eighty patients scheduled for first cesarean surgery were randomly allocated into 2 groups to receive either 1.5 mL lidocaine 5% with 0.5 mL sterile water (control group, n = 40) or 1.5 mL lidocaine 5% with 0.5 mL preservative-free magnesium sulfate 10% (magnesium group, n = 40). Neither epinephrine nor opioid was added to the treatment mixture. The duration of analgesia after spinal anesthesia (the time from local anesthetic injection to the first opioid request) and the duration of analgesia after surgery (the time between termination of the procedure and the time at which the first dose opioid was requested) were compared. The durations of analgesia after spinal anesthesia was significantly longer in the magnesium (160.8±49.1) than in the control group (113.3±27.3) and the durations of analgesia after surgery was significantly longer in the magnesium (74.5±47.5) than in the control group (26.6±25.1), (p = 0.001). There was no associated increase in adverse events in the group receiving intrathecal magnesium.
M.D. Gita Shoeibi, M.D. Mustafa Sadegi, M.D. Abolfazl Firozian and M.D. Farzaneh Tabassomi, 2007. The Additional Effect of Magnesium Sulfate to Lidocaine in Spinal Anesthesia for Cesarean Section. International Journal of Pharmacology, 3: 425-427.