The Effect of Intravenous Ketamine on Analgesic Requirement after Spinal Anesthesia in Women Undergoing Caesarean Section: a Randomized Clinical Trial

Background aim: The use of opioids for pain relief after cesarean section (C/S) can result in adverse maternal and neonatal outcomes. Therefore, it is important to consider non-opioid analgesics as an alternative. This study examined the effect of intravenous ketamine on analgesic requirement after spinal anesthesia in women undergoing C/S.Methods: This double-blind randomized clinical trial included 80 pregnant women under spinal anesthesia during a planned C/S, who were recruited from trainig hospitals of Mashhad, Iran between February and August 2022. The participants were selected using convenience sampling and assigned to two intervention (40) and control (40) groups through random allocation. The intervention group received intravenous ketamine (0.5 mg/kg) and midazolam (0.02 mg/kg) immediately after umbilical cord clamping, while the control group received midazolam alone (0.02 mg/kg). Pain scores were recorded at baseline, 6th, 12th, and 24th hours after elective C/S using the Visual Analog Scale(VAS), along with the amount of requiremen to analgesics. Data analysis was performed by SPSS software (version 16) using Chi-square, T-test and repeated measure ANOVA test.Results: A significant difference was seen in pain scores between the two groups at different hours and over time (P=0.009). The intervention group reported significantly lower levels of pain than the control group (P=0.002) and a significantly lower need for painkillers during the first hour (P=0.04).Conclusion: Administration of intravenous ketamine in elective C/S with spinal anesthesia in the first hour has a significant effect on pain relief Therefore, it can be considered the drug of choice for alleviating pain.