Comparison of Nalbuphine Versus Clonidine as an Adjuvant to Intrathecal Hyperbaric Bupivacaine in Orthopedic Lower Limb Surgeries: A Randomized Controlled Double-Blind Study

Background: Nalbuphine and clonidine are used as adjuvants to intrathecal local anesthetics, but studies on their comparative efficacy have shown inconsistent results. This study aimed to compare nalbuphine, clonidine, or normal saline as adjuvants to intrathecal hyperbaric bupivacaine in orthopedic lower limb surgeries. Method: Sixty-three American Society of Anesthesiologists (ASA) I/II patients between 18 and 60 years old with lower limb fractures were randomized into three groups (n=21 each). Patients with contraindications to spinal block, bilateral lower limb fractures, or long-term opioid therapy were excluded. The subarachnoid block was given in L3-L4 interspace. Group N received 1 mg of nalbuphine, group Cl received 30 mcg of clonidine, and group C received 0.5 ml of normal saline with 15 mg (0.5%) of hyperbaric bupivacaine. Sensory and motor block characteristics, hemodynamic variables and side effects were noted, and the data were analyzed using Student’s t-test, Mann-Whitney test, Chi-square test, and ANOVA followed by Tukey’s test. Results: Patients receiving intrathecal nalbuphine (group N) and clonidine (group Cl) had a faster onset of the sensory and motor block than controls (group C) (p=0.000). The time to two-segment regression was more prolonged in group Cl when compared to group N (p=0.000). Duration of spinal analgesia was 216.75 ± 25.96 minutes, 292.86 ± 24.92 minutes, and 178.50 ± 16.06 minutes in groups N, Cl, and C, respectively (p=0.000). The 24-hour rescue analgesic requirement was maximum in group C and least in group Cl (p=0.000). The three groups were comparable to each other in terms of side effects. Conclusion: Clonidine was found to be superior to nalbuphine as an intrathecal adjuvant with no significant side effects.