Spinal anaesthesia with bupivacaine provides reliable intraoperative anaesthesia but is limited by shorter postoperative analgesia. Intrathecal adjuvants have been evaluated to improve block duration and patient comfort. α2-adrenergic agonists, particularly clonidine and dexmedetomidine, have shown promise due to their sedative, analgesic, and opioid-sparing effects without significant respiratory depression.

This study aimed to compare intrathecal clonidine (30 mcg) and dexmedetomidine (3 mcg) as adjuvants to bupivacaine in patients undergoing lower abdominal surgeries.

MATERIALS AND METHODS

Design: Prospective, randomized, comparative study.
Population: 60 patients, ASA I–II, aged 18–65 years, scheduled for elective lower abdominal surgery.
Groups:
- Group C (n=30): Bupivacaine 12.5 mg + Clonidine 30 mcg
- Group D (n=30): Bupivacaine 12.5 mg + Dexmedetomidine 3 mcg

Assessments:
- Onset of sensory block (T10 level)
- Onset of motor block (Modified Bromage 3)
- Duration of analgesia (time to first rescue analgesic, tramadol 50 mg IV)
- Hemodynamic parameters (HR, MAP at intervals for 12h)
- Complications (hypotension, bradycardia, sedation)

Statistics: SPSS v20 used. Independent t-test, chi-square/Fisher’s exact test. p < 0.05 considered significant.

RESULTS

- Sensory block onset: 6.43 ± 2.87 min (clonidine) vs 6.04 ± 2.93 min (dexmedetomidine), p=0.600
- Motor block onset: 7.6 ± 2.85 min vs 7.02 ± 2.84 min, p=0.431
- Analgesia duration: 333.3 ± 94.0 min vs 367.7 ± 89.0 min, p=0.152
- Hemodynamics: HR and MAP trends comparable; occasional bradycardia/hypotension treated effectively.
- Complications: None had excessive sedation; adverse events minimal and comparable.

DISCUSSION

Both adjuvants provided comparable efficacy with stable hemodynamics. Dexmedetomidine showed a trend toward longer analgesia, consistent with prior studies. Clonidine, however, remains a cost-effective option, especially in resource-limited settings. Importantly, both agents were free of major complications at low doses, supporting their role as opioid-sparing alternatives.

CONCLUSION

Dexmedetomidine (3 mcg) and clonidine (30 mcg) are safe and effective intrathecal adjuvants to bupivacaine in spinal anaesthesia for lower abdominal surgeries. Dexmedetomidine may offer marginal clinical benefit, while clonidine remains more economical. Further multicentre trials with larger sample sizes are warranted.

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