Context: Achieving satisfactory postoperative analgesia with epidural opioids has been the subject of research many times. Aims: To evaluate postoperative pain relief in patients administered with epidural nalbuphine or tramadol for lower-limb surgery under combined spinal-epidural anesthesia. Settings: Tertiary hospital, Kanchipuram Dist, Tamil Nadu. Design:Prospective observational study. Materials and Methods: The study was done on patients undergoing lower-limb orthopedic procedures. The patients were assigned to either epidural nalbuphine (N) Group or epidural tramadol (T) Group. The convenience sampling technique was used until each group had 40 subjects. Group N received epidural 0.125 % bupivacaine with nalbuphine 0.2 mg/ml infusion@6ml/hr and Group T with epidural 0.125 % bupivacaine with tramadol2mg/ml infusion@6ml/hr started at sensory regression to T10 for postop analgesia. The pain severity was assessed using Visual Analog Scale (VAS) and sedation was assessed using Pasero Opioid-induced Sedation Scale (POSS). Intravenous paracetamol was used as rescue medication. Statistical analysis used: Chi-square test and unpaired t-test. Results: The mean sedation at 2 hrs was 1.65 ± 0.8 in tramadol and 2.8 ± 0.41 in the nalbuphine group. The difference was statistically significant (p - value < 0.001). The mean VAS at 12 hrs was 1.06 ± 0.4 in tramadol and 1.26 ± 0.44 in nalbuphine. At 24 hrs it was 0.86 ± 0.41 in tramadol and 1.05 ± 0.34 in nalbuphine group, with statistically significant differences (p - value < 0.05). In the tramadol group, 5 (12.5%) had vomiting and 6 (15%) were administered with IV
paracetamol. Conclusions: Nalbuphine was more effective in providing postoperative pain relief compared to Tramadol. Tramadol was associated with a higher incidence of nausea and vomiting.