Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 0 0 2026 06 08 1513 1513 Ahmed Hasan Anesthesia Department, Sohag University Hospital, Faculty of Medicine, Sohag University, Sohag, Egypt. Samar Osman Anesthesia Department, Sohag University Hospital, Faculty of Medicine, Sohag University, Sohag, Egypt. Osama Soliman Anesthesia Department, Sohag University Hospital, Faculty of Medicine, Sohag University, Sohag, Egypt. Elhaisam Taha Anesthesia Department, Sohag University Hospital, Faculty of Medicine, Sohag University, Sohag, Egypt. waleed Ahmed Anesthesia Department, Sohag University Hospital, Faculty of Medicine, Sohag University, Sohag, Egypt. 2025 12 08 2026 01 03 Background: Regional anesthesia is widely employed for infraumbilical and orthopedic surgeries due to its safety, cost-effectiveness, and ability to provide prolonged postoperative analgesia while attenuating autonomic and endocrine responses. The addition of intrathecal adjuvants to levobupivacaine has been shown to improve block characteristics and extend analgesia. Aim: To compare the effects of intrathecal fentanyl, dexmedetomidine, and nalbuphine as adjuvants to levobupivacaine with respect to block efficacy, duration of action, postoperative analgesia, and perioperative complications. Methods: This prospective, randomized, controlled clinical study was conducted at Sohag University Hospital on 120 ASA I–II patients aged 20–50 years undergoing lower abdominal and lower limb surgeries. Patients were allocated into four groups (n=30 each): Group L received levobupivacaine 15 mg alone; Group F received levobupivacaine + fentanyl 25 μg; Group D received levobupivacaine + dexmedetomidine 5 μg; Group N received levobupivacaine + nalbuphine 0.8 mg. Block characteristics, analgesia duration, hemodynamic parameters, adverse effects, and postoperative pain scores (VAS) were recorded. Statistical analysis used Student’s t-test and Chi-square/Fisher’s exact test, with p < 0.05 considered significant. Results: Dexmedetomidine produced the fastest sensory onset (3.1 ± 0.6 min), the highest sensory level (T4), the longest motor block duration (225.4 ± 21.8 min), and prolonged analgesia (338.7 ± 22.1 min). Fentanyl improved analgesia (258.3 ± 20.8 min) but was associated with pruritus (36.7%). Nalbuphine showed intermediate efficacy (249.7 ± 23.1 min) with fewer side effects (pruritus 6.7%). Levobupivacaine alone resulted in the shortest block and analgesia duration (165.8 ± 22.4 min). Hemodynamics remained stable across groups, though bradycardia was more frequent with dexmedetomidine (26.7%). VAS scores were significantly lower in the dexmedetomidine group during the early postoperative period (2–8 hours). Conclusion: Dexmedetomidine is the most effective intrathecal adjuvant to levobupivacaine for enhancing block quality and prolonging analgesia, though its use requires vigilance for bradycardia. Nalbuphine offers a balanced profile with moderate efficacy and fewer adverse effects, while fentanyl remains effective but is limited by pruritus. The choice of adjuvant should be individualized according to patient comorbidities and surgical requirements. https://aacc.tums.ac.ir/index.php/aacc/article/view/1513