Effect of Gabapentin Pretreatment on Hyperalgesia in Older Patients Undergoing Sequential Bilateral Cataract Surgery: A Prospective, Randomized Controlled Trial

Background/Objectives: To evaluate whether gabapentin pretreatment modulates neuronal excitability and attenuates second-eye hyperalgesia in patients undergoing sequential bilateral cataract surgery under monitored anesthesia care with retrobulbar block. Methods: We conducted a prospective, parallel-group, randomized controlled trial with blinded outcome assessors at a tertiary university hospital. Patients aged > 60 years undergoing elective sequential bilateral cataract surgeries with a 1-week interval were enrolled. Participants were randomized 1:1 to receive gabapentin (100 mg three times daily for 1 week between surgeries) or no pretreatment. The primary outcome was the incidence of hyperalgesia, defined as greater intraoperative pain during the second-eye surgery compared to the first. Secondary outcomes included preoperative anxiety level, intraoperative and postoperative pain score, opioid rescue requirements, and surgeon/patient satisfaction for first- and second-eye surgeries. Results: Sixty-four patients (128 eyes) were included and analyzed (31 per group). Hyperalgesia was lower in the gabapentin pretreatment group than in the control group (4 [12.9%] vs. 17 [54.8%], risk ratio 0.24, 95% confidence interval 0.09–0.63, p = 0.001). Maximum intraoperative pain significantly decreased from the first to the second surgery in the gabapentin pretreatment group, whereas it increased in the control group (mean difference [standard deviation], −1.48 [2.14] vs. 0.97 [1.96], p < 0.001). Preoperative anxiety improved similarly in both groups before the second surgery. Conclusions: Gabapentin pretreatment may represent a promising strategy for reducing second-eye hyperalgesia and improving perioperative pain-related outcomes in older patients undergoing sequential bilateral cataract surgery under monitored anesthesia care with retrobulbar block.