Spinal anaesthesia is widely preferred for elective lower abdominal surgeries because of its rapid onset, reliable sensory and motor blockade, reduced systemic drug exposure, and favourable perioperative recovery profile. Hyperbaric bupivacaine is commonly employed for subarachnoid blockade owing to its predictable anaesthetic effects. However, its limited duration of action may necessitate supplementary analgesia, particularly during prolonged procedures and the early postoperative period. Consequently, intrathecal adjuvants have gained considerable attention for improving block characteristics, extending postoperative analgesia, and reducing rescue analgesic requirements [1,2]. Among the available adjuvants, clonidine and dexmedetomidine are centrally acting alpha-2 adrenergic receptor agonists that enhance spinal anaesthesia through modulation of nociceptive transmission within the spinal dorsal horn. Clonidine produces analgesic and sedative effects by stimulating alpha-2 receptors and reducing neuronal excitability, whereas dexmedetomidine exhibits greater alpha-2 receptor selectivity and potent analgesic properties. Both agents may prolong sensory and motor blockade, although their administration can be associated with hypotension, bradycardia, and sedation. Kalbande et al. demonstrated improved block characteristics with intrathecal dexmedetomidine, while Alam et al. reported prolonged postoperative analgesia in patients undergoing lower abdominal surgeries [2,3]. A systematic review by Kumar et al. further confirmed significant improvements in sensory blockade, motor blockade, and analgesic duration following the addition of dexmedetomidine to intrathecal bupivacaine [4]. Recent comparative investigations have highlighted the potential advantages of these agents. Agrawal et al. demonstrated that clonidine significantly prolonged postoperative analgesia compared with nalbuphine in lower limb surgeries [5]. Manoharan et al. reported that dexmedetomidine provided a longer duration of blockade and delayed rescue analgesic requirements compared with clonidine when combined with hyperbaric levobupivacaine [6]. Subsequent investigations by Shafqat et al. and Shukla et al. supported the clinical effectiveness of intrathecal dexmedetomidine in enhancing spinal anaesthetic characteristics [7,8]. Gupta et al. also demonstrated favourable analgesic outcomes with dexmedetomidine during lower abdominal procedures [9]. A recent meta-analysis by Yang et al. suggested that dexmedetomidine provides superior sensory and motor blockade and prolongs analgesia compared with clonidine [10]. Despite these findings, uncertainty remains regarding the comparative clinical benefits of clonidine and dexmedetomidine specifically when administered with hyperbaric bupivacaine during elective lower abdominal surgeries. Variations in drug dosage, surgical populations, local anaesthetic formulations, and assessment methods limit direct comparisons. Therefore, the present prospective randomized study aims to compare intrathecal clonidine and dexmedetomidine as adjuvants to hyperbaric bupivacaine regarding the onset and duration of sensory and motor blockade, postoperative analgesic duration, rescue analgesic requirements, haemodynamic stability, and adverse effects, thereby identifying the more effective and clinically suitable adjuvant.

Study Design and Setting The present study was designed as a prospective, randomized, comparative study to evaluate the efficacy and safety of intrathecal clonidine and dexmedetomidine as adjuvants to hyperbaric bupivacaine in patients undergoing elective lower abdominal surgeries. The study was conducted in the Department of Anaesthesiology, DR VRK Women’s Medical College, Hyderabad. A total of 75 patients scheduled for elective lower abdominal surgeries under spinal anaesthesia were enrolled. The study aimed to compare the onset and duration of sensory and motor blockade, duration of postoperative analgesia, haemodynamic changes, rescue analgesic requirements, and adverse effects among the study groups. Sample Size and Sampling Technique The study comprised 75 patients who fulfilled the eligibility criteria. Patients were selected using consecutive sampling and randomly allocated into three groups of 25 patients each using a computer-generated randomization sequence. Allocation concealment was performed using sequentially numbered, opaque, sealed envelopes. Group A received intrathecal hyperbaric bupivacaine alone (control group), Group B received hyperbaric bupivacaine with clonidine, and Group C received hyperbaric bupivacaine with dexmedetomidine. The inclusion of a control group facilitated the comparison of both adjuvants with the standard local anaesthetic. Inclusion Criteria • Female patients aged 18–65 years. • Patients classified under American Society of Anesthesiologists (ASA) physical status I or II. • Patients who were scheduled for elective lower abdominal surgeries under spinal anaesthesia. • Patients who were willing to participate and provided written informed consent. • Patients who had no contraindications to subarachnoid blockade. Exclusion Criteria • Patients who refused spinal anaesthesia or study participation. • Patients with known hypersensitivity to bupivacaine, clonidine, or dexmedetomidine. • Patients with significant cardiovascular disorders, severe bradycardia, or uncontrolled hypotension. • Patients with coagulation abnormalities or those receiving anticoagulant therapy that contraindicated neuraxial anaesthesia. • Patients with infection at the proposed spinal injection site. • Patients with pre-existing neurological disorders or significant spinal deformities. • Patients with severe hepatic or renal dysfunction. • Patients receiving chronic opioid therapy or medications that were likely to interfere with the assessment of sensory blockade or analgesia. • Pregnant patients, unless obstetric procedures were specifically included in the approved study protocol. Study Tool The following instruments and assessment methods were used for collecting study-related information: • Structured case record form: This was used to document demographic characteristics, medical history, ASA classification, surgical details, and perioperative observations. • Multiparameter monitor: This was used to record heart rate, non-invasive blood pressure, mean arterial pressure, oxygen saturation, and electrocardiographic findings. • Pinprick sensation test: This was used to assess the onset, maximum level, and duration of sensory blockade. • Modified Bromage scale: This was used to evaluate the onset, intensity, and recovery of motor blockade. • Visual Analogue Scale (VAS): This was used to assess postoperative pain intensity using a 0–10 scale. • Sedation assessment scale: This was used to evaluate intraoperative sedation using a standardized sedation scoring system. • Adverse-event documentation sheet: This was used to record hypotension, bradycardia, nausea, vomiting, shivering, respiratory depression, and other complications. Study Procedure Following approval from the Institutional Ethics Committee and after obtaining written informed consent, eligible patients underwent a detailed pre-anaesthetic evaluation, including relevant clinical examinations and routine investigations. Standard fasting guidelines were followed, and baseline haemodynamic parameters were recorded before spinal anaesthesia. Intravenous access was established, and perioperative fluid management was performed according to institutional protocols. Under strict aseptic precautions, subarachnoid blockade was performed at the L3–L4 or L4–L5 intervertebral space using a suitable spinal needle. Patients in Group A received hyperbaric bupivacaine alone, Group B received hyperbaric bupivacaine combined with clonidine, and Group C received hyperbaric bupivacaine combined with dexmedetomidine. The doses of bupivacaine and adjuvants, as well as the final intrathecal injection volume, were standardized according to the approved study protocol before patient recruitment. Sensory blockade was evaluated using the pinprick method, and motor blockade was assessed using the modified Bromage scale. Haemodynamic parameters were monitored throughout the procedure and during the postoperative recovery period. Postoperative pain scores, time to first rescue analgesic administration, total rescue analgesic consumption, and adverse effects were documented systematically. Data Collection Data were collected using a structured case record form, and the following parameters were recorded: • Demographic characteristics: Age, height, weight, body mass index, and ASA physical status were recorded. • Surgical characteristics: The type of lower abdominal surgery and duration of the procedure were documented. • Baseline haemodynamic parameters: Heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and oxygen saturation were measured and recorded. • Sensory blockade characteristics: Time to onset, highest sensory block level, time to two-segment regression, and duration of sensory blockade were assessed. • Motor blockade characteristics: Time to onset, maximum Bromage score, and time to complete motor recovery were recorded. • Postoperative analgesia: Duration of effective analgesia, VAS scores at predefined intervals, and time to first rescue analgesic administration were documented. • Rescue analgesic requirements: The number of rescue doses and total analgesic consumption during the postoperative observation period were recorded. • Haemodynamic changes: Changes in heart rate and blood pressure were monitored and recorded at predefined intraoperative and postoperative intervals. • Sedation score: Intraoperative sedation was assessed using the selected standardized sedation scoring system. • Adverse effects: The incidence of hypotension, bradycardia, nausea, vomiting, shivering, respiratory depression, and other complications was recorded. Statistical Analysis The collected data were entered into Microsoft Excel and analysed using the Statistical Package for the Social Sciences (SPSS) software. Continuous variables were expressed as mean ± standard deviation or median with interquartile range, depending on data distribution, while categorical variables were presented as frequencies and percentages. Differences among the three groups were assessed using one-way analysis of variance (ANOVA) for normally distributed continuous variables or the Kruskal–Wallis test for non-normally distributed variables. The Chi-square test or Fisher’s exact test was applied to categorical variables. Appropriate repeated-measures methods were used to assess haemodynamic changes over time. Post-hoc pairwise comparisons were performed with adjustments for multiple testing wherever required. A p-value of less than 0.05 was considered statistically significant..

Table 1. Comparison of Demographic and Baseline Clinical Characteristics Among the Three Study Groups Parameter Group A (n=25) Group B (n=25) Group C (n=25) p-value Age (years) 37.3 ± 13.1 40.3 ± 9.2 38.4 ± 12.4 0.647 Weight (kg) 61.6 ± 10.4 61.5 ± 9.1 64.1 ± 10.3 0.580 Height (cm) 157.1 ± 5.6 158.6 ± 4.1 158.9 ± 6.0 0.434 BMI (kg/m²) 24.9 ± 3.4 24.4 ± 3.0 25.3 ± 3.0 0.595 ASA Grade I, n (%) 17 (68%) 16 (64%) 18 (72%) 0.832 ASA Grade II, n (%) 8 (32%) 9 (36%) 7 (28%) — Duration of surgery (min) 86.0 ± 16.1 89.2 ± 15.2 82.4 ± 13.8 0.287 Baseline heart rate (beats/min) 85.1 ± 9.6 82.1 ± 9.0 81.7 ± 8.6 0.355 Baseline MAP (mmHg) 90.8 ± 6.4 92.1 ± 6.7 91.3 ± 6.0 0.753 The demographic and baseline clinical characteristics were comparable across the three study groups. Mean age varied from 37.3 ± 13.1 years in Group A to 40.3 ± 9.2 years in Group B, without a statistically significant difference (p=0.647). Body weight, height, and BMI were similarly distributed among the groups (p>0.05). Most patients belonged to ASA Grade I, with no significant variation in ASA classification (p=0.832). The mean duration of surgery and baseline haemodynamic measurements were also comparable. These findings indicate an adequately balanced dataset for evaluating differences in anaesthetic efficacy and postoperative outcomes. Table 2. Comparison of Sensory Blockade Characteristics Among the Three Study Groups Sensory blockade parameter Group A Group B Group C p-value Onset of sensory blockade (min) 3.5 ± 0.6 3.1 ± 0.4 2.7 ± 0.4 <0.001 Time to achieve T10 level (min) 4.6 ± 0.6 4.2 ± 0.6 3.8 ± 0.3 <0.001 Time to maximum sensory level (min) 6.6 ± 0.8 6.3 ± 0.8 5.8 ± 0.5 <0.001 Time to two-segment regression (min) 102.2 ± 14.1 143.3 ± 19.2 176.0 ± 20.0 <0.001 Total duration of sensory blockade (min) 148.0 ± 18.3 203.4 ± 24.9 255.1 ± 29.1 <0.001 Values expressed as mean ± SD. Statistical analysis: one-way ANOVA. Sensory blockade characteristics demonstrated statistically significant differences among the three study groups. The mean onset of sensory blockade was shortest in Group C (2.7 ± 0.4 min), followed by Group B (3.1 ± 0.4 min) and Group A (3.5 ± 0.6 min), with p<0.001. Achievement of T10 sensory level and maximum sensory blockade was also earlier in Group C. The mean two-segment regression time was prolonged to 176.0 ± 20.0 minutes in Group C compared with 143.3 ± 19.2 minutes in Group B and 102.2 ± 14.1 minutes in Group A. Total sensory blockade duration was highest in Group C (255.1 ± 29.1 min), with significant differences among groups (p<0.001). These results shows a greater prolongation of sensory blockade with dexmedetomidine than with clonidine or bupivacaine alone. Table 3. Comparison of Motor Blockade Characteristics Among the Three Study Groups Motor blockade parameter Group A Group B Group C p-value Onset of motor blockade (min) 5.1 ± 0.5 4.9 ± 0.5 4.4 ± 0.7 <0.001 Time to Bromage Grade III (min) 7.0 ± 0.6 6.9 ± 0.6 6.6 ± 0.8 0.050 Maximum Bromage score 3 3 3 — Duration of motor blockade (min) 123.2 ± 17.7 169.6 ± 21.4 214.7 ± 23.5 <0.001 Time to complete motor recovery (min) 124.0 ± 18.0 169.2 ± 21.6 215.2 ± 23.0 <0.001 Values expressed as mean ± SD, except maximum Bromage score. Statistical analysis: one-way ANOVA. Maximum score was constant across groups. Motor blockade characteristics differed among the three study groups. The onset of motor blockade was fastest in Group C (4.4 ± 0.7 min), compared with Group B (4.9 ± 0.5 min) and Group A (5.1 ± 0.5 min), demonstrating statistical significance (p<0.001). The time to achieve Bromage Grade III was slightly shorter in Group C, although the overall comparison was borderline (p=0.050). The duration of motor blockade was substantially prolonged in Group C (214.7 ± 23.5 min), followed by Group B (169.6 ± 21.4 min) and Group A (123.2 ± 17.7 min). Complete motor recovery followed a similar pattern, with significant differences among the groups (p<0.001). These findings shows stronger prolongation of motor blockade with dexmedetomidine, although delayed motor recovery remains an important clinical consideration. Table 4. Comparison of Postoperative Analgesic Characteristics and Rescue Analgesic Requirements Among the Three Study Groups Analgesic parameter Group A Group B Group C p-value Duration of effective analgesia (min) 194.3 ± 31.5 267.9 ± 45.0 342.4 ± 40.6 <0.001 Time to first rescue analgesic (min) 205.4 ± 30.4 277.1 ± 44.1 354.4 ± 42.3 <0.001 VAS at 2 hours 1.4 ± 0.9 1.1 ± 0.8 0.9 ± 0.8 0.125 VAS at 4 hours 2.9 ± 1.0 2.0 ± 0.8 1.3 ± 0.9 <0.001 VAS at 6 hours 2.9 ± 1.0 2.4 ± 0.8 2.2 ± 1.3 0.078 VAS at 12 hours 3.2 ± 1.1 2.7 ± 0.9 2.6 ± 1.3 0.290 VAS at 24 hours 2.6 ± 1.0 2.6 ± 0.7 2.9 ± 0.9 0.477 Total rescue analgesic dose (mg/24 h) 143.2 ± 20.1 101.4 ± 18.9 80.7 ± 21.7 <0.001 Number of rescue doses (24 h) 2.6 ± 0.5 1.9 ± 0.4 1.6 ± 0.5 <0.001 Values expressed as mean ± SD. ANOVA was applied to continuous outcomes; Kruskal–Wallis tests to VAS scores and rescue-dose counts. Postoperative analgesic efficacy showed substantial differences among the three groups. The duration of effective analgesia was longest in Group C (342.4 ± 40.6 min), followed by Group B (267.9 ± 45.0 min) and Group A (194.3 ± 31.5 min), with p<0.001. Similarly, the time to first rescue analgesic administration was significantly delayed in Group C (354.4 ± 42.3 min). Pain scores at four hours were significantly lower in Group C (1.3 ± 0.9) compared with Groups B and A (p<0.001), whereas differences at other recorded intervals were not statistically significant. Total rescue analgesic consumption was lowest in Group C (80.7 ± 21.7 mg), followed by Group B (101.4 ± 18.9 mg) and Group A (143.2 ± 20.1 mg). These findings shows a clinically relevant analgesic advantage for dexmedetomidine over clonidine and bupivacaine alone. Table 5. Comparison of Intraoperative Haemodynamic Parameters and Adverse Effects Among the Three Study Groups Parameter Group A Group B Group C p-value Baseline heart rate (beats/min) 85.1 ± 9.6 82.1 ± 9.0 81.7 ± 8.6 0.355 Heart rate at 10 min 80.6 ± 9.5 76.7 ± 9.2 74.9 ± 9.0 0.090 Heart rate at 30 min 81.6 ± 9.8 75.5 ± 9.1 74.5 ± 9.5 0.020 Heart rate at 60 min 83.8 ± 10.3 76.6 ± 10.0 77.2 ± 8.9 0.018 Baseline MAP (mmHg) 90.8 ± 6.4 92.1 ± 6.7 91.3 ± 6.0 0.753 MAP at 10 min 84.3 ± 7.2 83.9 ± 6.6 81.0 ± 7.5 0.203 MAP at 30 min 86.2 ± 7.5 84.4 ± 7.9 81.5 ± 7.2 0.090 MAP at 60 min 87.6 ± 6.5 85.6 ± 7.0 86.5 ± 6.0 0.550 Hypotension, n (%) 2 (8%) 4 (16%) 5 (20%) 0.474 Bradycardia, n (%) 1 (4%) 3 (12%) 4 (16%) 0.376 Nausea/vomiting, n (%) 3 (12%) 2 (8%) 2 (8%) 0.854 Shivering, n (%) 4 (16%) 2 (8%) 1 (4%) 0.332 Excessive sedation, n (%) 0 (0%) 2 (8%) 4 (16%) 0.114 Haemodynamic values expressed as mean ± SD; adverse events as n (%). Displayed haemodynamic p-values are time-specific one-way ANOVA comparisons, not longitudinal interaction tests.. The baseline haemodynamic parameters were comparable across the three study groups. Heart rate decreased following spinal anaesthesia in all groups, with significant differences observed at 30 minutes (p=0.020) and 60 minutes (p=0.018). Group C demonstrated the lowest mean heart rate at 30 minutes (74.5 ± 9.5 beats/min), followed by Group B and Group A. Mean arterial pressure decreased after spinal anaesthesia, although between-group differences were not statistically significant at the measured intervals. Hypotension and bradycardia occurred more frequently in Group C (20% and 16%, respectively), whereas shivering was most frequent in Group A (16%). No statistically significant differences were demonstrated in the recorded adverse-event frequencies, suggesting that larger studies would be necessary to assess comparative safety with greater precision. Table 6. Correlation Between Duration of Sensory Blockade and Duration of Postoperative Analgesia Study group Correlation parameters Pearson's r p-value Group A (n=25) Sensory blockade duration vs analgesic duration 0.637 <0.001 Group B (n=25) Sensory blockade duration vs analgesic duration 0.739 <0.001 Group C (n=25) Sensory blockade duration vs analgesic duration 0.796 <0.001 Overall (n=75) Sensory blockade duration vs analgesic duration 0.929 <0.001 Pearson correlation coefficients were calculated using individual patient-level paired observations. All tests are two-sided. A statistically significant positive correlation was observed between sensory blockade duration and postoperative analgesic duration across the three study groups. Group A demonstrated a moderate-to-strong positive correlation (r=0.637, p<0.001), indicating that longer sensory blockade was associated with prolonged postoperative analgesia. A stronger association was observed in Group B (r=0.739, p<0.001). Group C demonstrated the highest within-group correlation (r=0.796, p<0.001), reflecting a consistent relationship between the two parameters. The overall correlation coefficient of 0.929 indicated a very strong positive association across all 75 observations, although this pooled relationship was partly influenced by differences between treatment groups. These findings illustrate that prolonged sensory blockade and extended postoperative analgesia may be closely related, without establishing a causal relationship. Table 7. Correlation Between Duration of Motor Blockade and Time to First Rescue Analgesic Administration Study group Correlation parameters Pearson's r p-value Group A (n=25) Motor blockade duration vs time to first rescue analgesic 0.510 0.009 Group B (n=25) Motor blockade duration vs time to first rescue analgesic 0.668 <0.001 Group C (n=25) Motor blockade duration vs time to first rescue analgesic 0.777 <0.001 Overall (n=75) Motor blockade duration vs time to first rescue analgesic 0.914 <0.001 A significant positive correlation was demonstrated between the duration of motor blockade and time to first rescue analgesic administration in all three groups. Group A showed a moderate positive correlation (r=0.510, p=0.009). The association was stronger in Group B (r=0.668, p<0.001), indicating that longer motor blockade was associated with delayed analgesic administration. Group C demonstrated the strongest within-group relationship (r=0.777, p<0.001). The pooled correlation coefficient was 0.914 (p<0.001), suggesting a very strong overall association, partly attributable to differences among the study groups. These findings illustrate the importance of considering motor recovery alongside prolonged analgesic effects when evaluating intrathecal adjuvants.

Spinal anaesthesia with hyperbaric bupivacaine is widely employed for lower abdominal surgeries because of its reliable sensory and motor blockade. However, its relatively limited duration of postoperative analgesia has encouraged the use of intrathecal adjuvants. The comparative analysis of 75 observations demonstrated that both clonidine and dexmedetomidine improved block characteristics compared with bupivacaine alone, with dexmedetomidine producing the most prolonged sensory blockade, motor blockade, and postoperative analgesia. Baseline demographic characteristics, ASA physical status, and surgical duration were comparable among the three groups, permitting meaningful evaluation of the differences in anaesthetic outcomes. The onset of sensory blockade was shortest in the dexmedetomidine group (2.7 ± 0.4 minutes), followed by the clonidine group (3.1 ± 0.4 minutes) and control group (3.5 ± 0.6 minutes), with a statistically significant difference (p<0.001). Similarly, the duration of sensory blockade was considerably prolonged with dexmedetomidine (255.1 ± 29.1 minutes) compared with clonidine (203.4 ± 24.9 minutes) and bupivacaine alone (148.0 ± 18.3 minutes). These findings are consistent with the comparative investigation by Manoharan et al. [6], which demonstrated prolonged sensory blockade with dexmedetomidine compared with clonidine. The increased affinity of dexmedetomidine for alpha-2 adrenergic receptors may contribute to stronger inhibition of nociceptive transmission at the spinal level. Motor blockade followed a similar pattern, with the longest duration observed in the dexmedetomidine group (214.7 ± 23.5 minutes), followed by the clonidine group (169.6 ± 21.4 minutes) and control group (123.2 ± 17.7 minutes). Singh et al. [11] demonstrated that clonidine administered as oral or intramuscular premedication prolonged sensory and motor blockade compared with bupivacaine alone, supporting the broader anaesthetic effects of alpha-2 agonists. However, the systemic administration routes used in their investigation differ from intrathecal administration and should not be considered directly equivalent. Postoperative analgesia represented another important outcome. The duration of effective analgesia was longest with dexmedetomidine (342.4 ± 40.6 minutes), compared with clonidine (267.9 ± 45.0 minutes) and control treatment (194.3 ± 31.5 minutes). Rescue analgesic consumption was also lowest in the dexmedetomidine group. Cook et al. [12] reported that intrathecal clonidine was associated with delayed analgesic requests and reduced postoperative opioid consumption following caesarean delivery in patients with opioid use disorder. Although their patient population differed, the findings support the potential analgesic benefits of clonidine. The prolonged analgesic effect of dexmedetomidine is further supported by Mo et al. [13], who investigated intrathecal dexmedetomidine combined with ropivacaine during caesarean delivery. Their investigation demonstrated the anaesthetic dose-modifying potential of dexmedetomidine, although differences in local anaesthetic agents limit direct comparison. More recently, Vozzo et al. [14] reviewed evidence concerning intrathecal dexmedetomidine in obstetric anaesthesia and highlighted its potential clinical utility alongside the need for further safety evaluation. Boshoff et al. [15] reported reduced postoperative pain scores with intrathecal dexmedetomidine compared with fentanyl in their systematic review, particularly during the early postoperative period. Regarding haemodynamic stability, heart rate decreased after spinal anaesthesia in all three groups, with significant between-group differences at 30 and 60 minutes. Hypotension occurred in 20% of the dexmedetomidine group, 16% of the clonidine group, and 8% of controls, although these differences were not statistically significant. Takalo et al. [16] similarly observed improved postoperative analgesia and reduced opioid requirements with intrathecal dexmedetomidine but reported an increased incidence of intraoperative hypotension, emphasizing the importance of haemodynamic monitoring. Correlation analysis demonstrated strong positive relationships between sensory blockade duration and postoperative analgesic duration (r=0.929, p<0.001), and between motor blockade duration and time to first rescue analgesia (r=0.914, p<0.001). These pooled correlations were partly influenced by treatment-group differences and therefore should not be interpreted as evidence of causation. The principal limitations include the relatively small group sizes, absence of long-term neurological assessment, and dependence of outcomes on drug dosage and perioperative analgesic protocols. Furthermore, prolonged motor blockade may delay postoperative mobilization. Larger randomized studies are required to determine optimal dosing and establish comparative safety.

The comparative analysis shows that intrathecal dexmedetomidine, when combined with hyperbaric bupivacaine, may provide faster sensory blockade, prolonged sensory and motor blockade, extended postoperative analgesia, and reduced rescue analgesic requirements compared with clonidine and bupivacaine alone. Both alpha-2 adrenergic agonists appear promising for improving spinal anaesthetic characteristics. However, prolonged motor recovery and potential haemodynamic adverse effects require consideration. These findings provide a rationale for evaluating dexmedetomidine as an intrathecal adjuvant in a properly conducted prospective randomized clinical trial.

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