Comparison of Perioperative Single-Dose Systemic Dexamethasone Versus Placebo for Prolongation of Postoperative Analgesia in Term Parturients Undergoing Cesarean Section Under Spinal Anesthesia.

Background and objective Postoperative pain management following cesarean section under spinal anesthesia remains a significant clinical challenge, with limited analgesic duration frequently necessitating rescue interventions. Dexamethasone, a synthetic corticosteroid with established anti-inflammatory and analgesic properties, has demonstrated potential for prolonging neuraxial anesthesia effects. This randomized controlled trial (RCT) aimed to evaluate the efficacy of perioperative single-dose systemic dexamethasone versus placebo for prolongation of postoperative analgesia in term parturients undergoing cesarean section under spinal anesthesia, with secondary assessment of antiemetic and anti-shivering effects. Methodology This RCT was conducted at a tertiary care hospital over 12 months, recruiting 60 American Society of Anesthesiologists physical status grade II (ASA PS II) parturients aged 20-35 years undergoing elective cesarean section under spinal anesthesia. Participants were randomly allocated using the envelope method into two groups of 30 patients each. The dexamethasone group received intravenous dexamethasone 0.1 mg/kg diluted to 2 mL, while the placebo group received 2 mL normal saline as a placebo, administered 15 minutes before spinal anesthesia. Standardized spinal anesthesia was performed using 2 mL hyperbaric bupivacaine 0.5% with 20 mcg fentanyl. Postoperative assessment included visual analog scale (VAS) pain scores, sensory and motor blockade characteristics, and incidence of nausea, vomiting, and shivering, monitored every 30 minutes for 24 hours. Results Demographic characteristics demonstrated no statistically significant differences between groups, with mean ages of 25.70 ± 3.45 years in the dexamethasone group versus 25.90 ± 2.82 years in the placebo group. Dexamethasone administration significantly prolonged postoperative analgesia, with statistically significant VAS score differences observed from 240 to 750 minutes postoperatively. At 360 minutes, mean VAS scores were 0.00 ± 0.00 in the dexamethasone group versus 3.47 ± 1.46 in the placebo group (13.3%), representing peak analgesic difference. Sensory blockade regression demonstrated significant prolongation at 90 minutes and 210 minutes in the dexamethasone group. Motor blockade recovery showed no significant inter-group differences, with complete recovery achieved by 270 minutes in both groups. Postoperative nausea and vomiting incidence were 13.3% (n = 4) in the dexamethasone group versus 20% (n = 6) in the placebo group, although not statistically significant. Shivering occurred in one (3.3%) patient in the dexamethasone group versus none in the placebo group. Conclusion Perioperative single-dose intravenous dexamethasone 0.1 mg/kg significantly prolongs postoperative analgesia following cesarean section under spinal anesthesia, extending analgesic duration by approximately 270 minutes with an excellent safety profile. These findings support routine clinical implementation for enhanced maternal comfort and reduced rescue analgesic requirements.