Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 0 0 2026 02 23 1546 1546 Goli Aezzi Pashakollaei Department of Anesthesiology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. Frashad Hassanzadeh Kiabi Department of Anesthesiology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. Samira Sobhani Department of Anesthesiology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. Keihan Shabankhani Department of Anesthesiology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. Babak Kabiri Department of Anesthesiology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. Hossein Meskar Department of Anesthesiology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. 2025 12 27 2026 02 14 Background: Effective postoperative pain management after cesarean section enhances maternal recovery, facilitates early newborn care, and reduces postoperative complications. Due to the limitations and adverse effects of neuraxial opioids, non-opioid adjuvants have become an attractive alternative. This study compared the analgesic efficacy of dexmedetomidine and low-dose neostigmine as adjuvants to bupivacaine in spinal anesthesia for cesarean delivery. Methods: In this double-blind randomized clinical trial, 110 women undergoing elective cesarean were randomly allocated to receive either dexmedetomidine plus bupivacaine (Group D) or neostigmine plus bupivacaine (Group N). Demographic and intraoperative data were recorded. Sensory and motor block characteristics, postoperative pain intensity (VAS scores at 2, 4, 8, and 12 hours), time to first analgesic request, total 24-hour analgesic consumption, sedation levels, muscle relaxation quality, Apgar scores, and side effects (nausea, vomiting, shivering, pruritus) were assessed. Results: Baseline characteristics, sedation scores, muscle relaxation quality, and neonatal outcomes were comparable between groups. The onset of sensory and motor block was significantly faster in the neostigmine group, whereas their regression was markedly prolonged in the dexmedetomidine group (P<0.001). Pain scores were consistently lower, the first analgesic request was delayed, and total analgesic use was reduced in Group D (P<0.001). Nausea and vomiting occurred more frequently in Group N (P=0.007). Conclusion: Dexmedetomidine as an intrathecal adjuvant to bupivacaine provides superior and longer-lasting analgesia with fewer gastrointestinal side effects than neostigmine in cesarean sections under spinal anesthesia. https://aacc.tums.ac.ir/index.php/aacc/article/view/1546