Effect of preoperative gabapentin on postoperative pain and tramadol consumption after minilap open cholecystectomy: a randomized double-blind, placebo-controlled trial.

PURPOSE OF REVIEW: To evaluate the efficacy of a single preoperative dose of 600 mg of gabapentin for reducing postoperative pain and tramadol consumption after minilap open cholecystectomy.

METHOD: A total of 120 adult patients of either sex were randomly assigned to receive 600 mg of gabapentin or a matched placebo orally 2 h before operation in a double-blind manner. All the patients received gabapentin using the same technique. Postoperative analgesia was provided with intravenous patient-controlled analgesia with tramadol using a 50-mg initial bolus dose, 20-mg incremental dose, 15-min lockout interval and 4-h limit of 240 mg. Patients were assessed at 0, 2, 4, 8, 12, 24 and 48 h after operation for verbal analogue pain scores at rest and at movement. Consumption of tramadol on first and second postoperative days and any adverse effects were also recorded.

RESULTS: Verbal analogue pain scores were significantly lower on first postoperative day at all times of observation both at rest and at movement in gabapentin group than in placebo group (P<0.01). Tramadol consumption was also reduced by 33% in gabapentin group. But pain scores and tramadol consumption were similar in two groups on second postoperative day. Sedation was common but the incidence of postoperative nausea and vomiting was significantly lower in gabapentin group.

CONCLUSION: Preoperative administration of 600 mg of gabapentin resulted in significant reduction in postoperative verbal analogue pain scores at rest and at movement as well as tramadol consumption compared with placebo on first postoperative day. Lower incidence of nausea and vomiting was an additional advantage. Sedation was the commonest side effect.