Comparison of the Effects of Intrathecal Meperidine and Morphine on Incidence and Intensity of Shivering After Caesarean Sections Under Spinal Anesthesia: A Randomized Controlled Trial

Background Shivering is a common unpleasant problem in parturients undergoing cesarean section under spinal anesthesia. Therefore, attempts for solving this problem are rational. Objectives To evaluate and compare the effect of intrathecal meperidine with morphine on the incidence and intensity of shivering and other side-effects during delivery under spinal anesthesia. Methods In a double blind randomized controlled trial, 90 parturient women who were scheduled for elective cesarean delivery under spinal anesthesia were selected conveniently and randomly divided in 3 groups at the Besat hospital, which is a tertiary referral hospital in Sanandaj, Iran, from March to October 2013. Spinal anesthesia was applied using 12.5 mg of hyperbaric bupivacaine 0.5% combined with 10 mg meperidine in group P (n = 30), 12.5 mg of hyperbaric bupivacaine 0.5% combined with 0.2 mg morphine in group M (n = 30), and 12.5 mg of hyperbaric bupivacaine 0.5% combined with 0.5 mL saline in group S (n = 30). Results Incidence of shivering in the meperidine group (6.7%) was significantly lower than the morphine (40%) and control groups (67.7%, P = 0.0001). The intensity of shivering in the meperidine group (0.13) was significantly lower than the morphine (0.73) and control groups (1.43, P = 0.001). There was no clinically significant difference in anesthesia’s side effects between the 3 groups. Conclusions According to the study results, adding either meperidine or morphine to hyperbaric bupivacaine during spinal anesthesia for cesarean section decreases the incidence and severity of shivering without increasing the side effects. However, intrathechal meperidine is superior for this purpose.