PRE-EMPTIVE ORAL PREGABALIN VERSUS ORAL CLONIDINE FOR POSTOPERATIVE ANALGESIA FOLLOWING LOWER LIMB ORTHOPAEDIC SURGERY UNDER SPINAL ANAESTHESIA: A PROSPECTIVE RANDOMIZED DOUBLE-BLIND PLACEBO-CONTROLLED TRIAL

Abstract

Background: Effective postoperative pain control is essential after lower limb orthopaedic surgery to facilitate early mobilization, improve patient comfort, and reduce analgesic-related complications. Pregabalin and clonidine have been used as pre-emptive analgesic agents; however, evidence directly comparing their efficacy in patients undergoing spinal anaesthesia remains limited. This study compared the postoperative analgesic efficacy of oral pregabalin and oral clonidine in lower limb orthopaedic surgery performed under spinal anaesthesia.

Methods: This prospective, randomized, double-blind, placebo-controlled study included 90 ASA physical status I–II patients aged 18–65 years undergoing elective lower limb orthopaedic surgery. Patients were randomly allocated into three equal groups (n=30 each): Group A received oral clonidine 150 μg, Group B received oral pregabalin 150 mg, and Group C received placebo one hour before surgery. All patients underwent spinal anaesthesia with 3 mL of 0.5% hyperbaric bupivacaine. Postoperative pain was assessed using the Visual Analogue Scale (VAS). Duration of analgesia, time to first rescue analgesia, total diclofenac consumption, sedation scores, and adverse effects were recorded during the first 24 postoperative hours.

Results: Baseline demographic characteristics and spinal block parameters were comparable among the three groups (p>0.05). Patients receiving pregabalin demonstrated significantly lower postoperative VAS scores throughout the study period compared with clonidine and placebo (p<0.05). The duration of analgesia was longest in the pregabalin group (689±136 min), followed by the clonidine (517±107 min) and placebo groups (381±100 min) (p<0.001). Time to first rescue analgesia was significantly prolonged with pregabalin (572±136 min) compared with clonidine (400±106 min) and placebo (264±102 min) (p<0.001). Total postoperative diclofenac consumption was lowest with pregabalin (80.0±19.0 mg), compared with clonidine (110.0±38.1 mg) and placebo (182.5±37.8 mg) (p<0.001). Adverse effects were mild and comparable across all groups.

Conclusion: Preoperative oral pregabalin (150 mg) provided superior postoperative analgesia compared with oral clonidine (150 μg) and placebo by reducing pain intensity, prolonging analgesia, delaying rescue analgesic requirement, and decreasing postoperative analgesic consumption without increasing clinically significant adverse effects. Oral pregabalin may therefore be considered an effective component of multimodal analgesia for lower limb orthopaedic surgery performed under spinal anaesthesia.