Gabapentin for the prevention of postoperative pain after vaginal hysterectomy

Gabapentin alleviates and/or prevents acute nociceptive and inflammatory pain both in animals and volunteers, especially when given before trauma. Gabapentin might also reduce postoperative pain. To test the hypothesis that gabapentin reduces the postoperative need for additional pain treatment (postoperative opioid sparing effect of gabapentin in humans), we gave 1200 mg of gabapentin or 15 mg of oxazepam (active placebo) 2.5 h prior to induction of anaesthesia to patients undergoing elective vaginal hysterectomy in an active placebo-controlled, double blind, randomised study. Gabapentin reduced the need for additional postoperative pain treatment (PCA boluses of 50 μg of fentanyl) by 40% during the first 20 postoperative hours. During the first 2 postoperative hours pain scores at rest and worst pain score (VAS 0–100 mm) were significantly higher in the active placebo group compared to the gabapentin-treated patients. Additionally, pretreatment with gabapentin reduced the degree of postoperative nausea and incidence of vomiting/retching possibly either due to the diminished need for postoperative pain treatment with opioids or because of an anti-emetic effect of gabapentin itself. No preoperative differences between the two groups were encountered with respect to the side effects of the premedication. However, 15 mg oxazepam was more effective in relieving preoperative anxiety than 1200 mg gabapentin.