Preoperative Gabapentin for Acute Post-thoracotomy Analgesia: A Randomized, Double-Blinded, Active Placebo-Controlled Study

Background: The role of preoperative gabapentin in postoperative pain management is not clear, particularly in patients receiving regional blockade. Patients undergoing thoracotomy benefit from epidural analgesia but still may experience significant postoperative pain. We examined the effect of preoperative gabapentin in thoracotomy patients. Methods: Adults undergoing elective thoracotomy were enrolled in this prospective, randomized, double-blinded, placebo-controlled study, and randomly assigned to receive 600mg gabapentin or active placebo (12.5mg diphenhydramine) orally within 2hours preoperatively. Standardized management included thoracic epidural infusion, intravenous patient-controlled opioid analgesia, acetaminophen and ketorolac. Pain scores, opioid use and side effects were recorded for 48hours. Pain was also assessed at 3months. Results: One hundred twenty patients (63 placebo and 57 gabapentin) were studied. Pain scores did not significantly differ at any time point (P=0.53). Parenteral and oral opioid consumption was not significantly different between groups on postoperative day 1 or 2 (P>0.05 in both cases). The frequency of side effects such as nausea and vomiting or respiratory depression was not significantly different between groups, but gabapentin was associated with decreased frequency of pruritus requiring nalbuphine (14% gabapentin vs. 43% control group, P<0.001). The frequency of patients experiencing pain at 3months post-thoracotomy was also comparable between groups (70% gabapentin vs. 66% placebo group, P=0.72). Conclusions: A single preoperative oral dose of gabapentin (600mg) did not reduce pain scores or opioid consumption following elective thoracotomy, and did not confer any analgesic benefit in the setting of effective multimodal analgesia that included thoracic epidural infusion.