Background: Spinal anesthesia is widely used for infraumbilical surgeries due to its rapid onset and reliable blockade. However, the limited duration of action of hyperbaric bupivacaine necessitates the use of adjuvants to enhance and prolong postoperative analgesia. Nalbuphine hydrochloride, a mixed μ-antagonist and κ-agonist opioid, has shown promising results as an intrathecal adjuvant with minimal side effects. Aim: To evaluate and compare the anesthetic efficacy of intrathecal nalbuphine combined with 0.5% hyperbaric bupivacaine versus 0.5% hyperbaric bupivacaine alone in patients undergoing infraumbilical surgeries. Methods: This prospective randomized controlled study was conducted at Sree Mookambika Institute of Medical Sciences, Kulasekharam, Tamil Nadu, India, from July 2024 to August 2025. A total of 60 patients (ASA I–II), aged 30–60 years, were randomly divided into two groups. Group A received intrathecal 0.5% hyperbaric bupivacaine with 0.5 mg nalbuphine, while Group B received 0.5% hyperbaric bupivacaine alone. Parameters assessed included onset and duration of sensory and motor block, duration of postoperative analgesia, hemodynamic variables, and adverse effects. Statistical analysis was performed using SPSS software, with p < 0.05 considered significant. Results: The addition of nalbuphine resulted in a significantly faster onset of sensory and motor blockade compared to the control group (p < 0.05). The duration of sensory block, motor block, and postoperative analgesia was significantly prolonged in the nalbuphine group. Hemodynamic parameters remained stable in both groups, and no significant increase in adverse effects was observed. Conclusion: Intrathecal nalbuphine (0.5 mg) as an adjuvant to 0.5% hyperbaric bupivacaine provides superior anesthetic efficacy with prolonged postoperative analgesia and stable hemodynamics. It is a safe and effective option for enhancing spinal anesthesia in infraumbilical surgeries.

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