Optimal dose of pre-incision/post-incision gabapentin for pain relief following lumbar laminectomy: a randomized study

Background: Gabapentin has been introduced as an effective agent for post-operative pain control. This study aimed to test the effects of pre- and post-incision administration of different doses of gabapentin on post-operative morphine requirement and pain following lumbar laminectomy. Methods: In this randomized clinical trial, 175 patients were allocated into seven groups of 25 patients each to receive placebo or gabapentin 600, 900 or 1200 mg pre- or post-incision. Total patient-controlled intravenous morphine consumption during the first 24 post-operative hours, and the time to the first demand for morphine were recorded. Pain score at rest (visual analogue scale) was recorded every 30 min in the first 4 h and then every 2 h until 24 h post-operatively. Side-effects were observed. Results: In the first 12 h, morphine consumption was less, pain scores were lower and the time to the first demand for analgesia was longer in groups receiving gabapentin 900 or 1200 mg either pre- or post-incision, compared with placebo and gabapentin 600 mg (P<0.001). There was no difference between gabapentin 900 and 1200 mg. Pain score, morphine consumption and time to the first demand for analgesia in equal pre- or post-incision doses of gabapentin were not significantly different. No differences in the side-effects were observed between groups. Conclusion: Gabapentin 900 or 1200 mg, administered either pre- or post-incision, was found to be effective in pain management following lumbar laminectomy. Similar doses of gabapentin provide the same post-operative analgesia whether administered pre- or post-incision.