Effect of preemptive gabapentin on postoperative pain relief and morphine consumption following lumbar laminectomy and discectomy - A randomized, double-blinded, placebo-controlled study

Synergism between gabapentin and morphine in treating incisional pain has been demonstrated in animal experiments and clinical studies. The efficacy of gabapentin for treatment of perioperative pain remains controversial. This study was designed to detect the influence of gabapentin premedication on morphine consumption in the immediate postoperative period in patients undergoing lumbar laminectomy and discectomy. Either gabapentin 800 mg (in two equally divided doses) or placebo was given preoperatively to 60 adult patients undergoing elective lumbar laminectomy or discectomy in a double-blinded, placebo-controlled, randomized study. Standard general anesthesia was given to all the patients. Morphine was administered via patient-controlled analgesia pump in the immediate postoperative period for first 8 hours. Pain at rest and on movement was assessed using a Verbal Rating Scale (VRS) every 2 hours for the first 8 postoperative hours. There were no differences in demographics or surgical duration between the two groups. The amount of fentanyl administered in the intraoperative period was similar between the two groups. In the postoperative period, the VRS score for pain at 0, 2, 4, 6, and 8 hours was not significantly different between the two groups. Highest median VRS score was recorded at 0 hours postoperatively in both groups (VRS: rest 6, movement = 8 in placebo group; rest = 6, movement = 8 in gabapentin group). Total morphine consumption and side effects were similar in the two groups. Gabapentin does not decrease the morphine requirement or morphine side effects in the immediate postoperative period following lumbar laminectomy and discectomy.