Premedication with gabapentin, Alprazolam or a placebo for abdominal hysterectomy: Effect on preoperative anxiety, Postoperative pain and morphine consumption

Background and Aims: Utility of gabapentin for preoperative anxiolysis as compared to commonly administered alprazolam is not evident. The aim of the present study was to compare the effects of preoperative oral gabapentin 600 mg, alprazolam 0.5 mg or a placebo on preoperative anxiety along with postoperative pain and morphine consumption. Methods: Seventy five patients scheduled for abdominal hysterectomy under general anaesthesia were included. Groups gabapentin, alprazolam and placebo, received oral gabapentin 600 mg, alprazolam 0.5 mg and one capsule of oral Bcomplex forte with Vitamin C respectively, on the night prior to surgery and 2 h prior to surgery. Visual analogue scale (VAS) was used to measure the anxiety and postoperative pain. All patients received patientcontrolled analgesia. Statistical tests used were Kruskal–Wallis test, Wilcoxon signed rank test and oneway ANOVA. Results: Alprazolam provided significant anxiolysis (median [interquartile range] baseline VAS score 35 [15.5, 52] to 20 [6.5, 34.5] after drug administration; P = 0.007). Gabapentin did not provide significant decrease in anxiety (median [interquartile range] VAS score 21 [7.5, 41] to 20 [6.5, 34.5]; P = 0.782). First analgesic request time (median [interquartile range in minutes]) was longer in group gabapentin (17.5 [10, 41.25]) compared to group placebo (10 [5, 15]) (P = 0.019) but comparable to that in group alprazolam (15 [10, 30]). Cumulative morphine consumption at different time periods and total morphine consumption (mean [standard deviation]) at the end of study period (38.65 [18.04], 39.91 [15.73], 44.29 [16.02] mg in group gabapentin, alprazolam and placebo respectively) were comparable. Conclusion: Gabapentin 600 mg does not have significant anxiolytic effect compared to alprazolam 0.5 mg. Alprazolam 0.5 mg was found to be an effective anxiolytic in the preoperative period. Neither alprazolam nor gabapentin, when compared to placebo showed any opioid sparing effects postoperatively.