Gabapentin provides effective postoperative analgesia whether administered pre-emptively or post-incision

Abstract

Purpose: We investigated the effects of pre-incision and post-incision administration of gabapentin on postoperative pain and fentanyl consumption associated with open donor nephrectomy. Methods: Sixty ASA I subjects were randomly allocated into three groups to receive gabapentin 600 mg two hours before surgery and placebo after surgical incision (pre-incision group), placebo two hours before surgery and gabapentin 600 mg after surgical incision (post-incision group), or placebo two hours before surgery and after surgical incision (placebo group). After surgery, pain was assessed using a visual analogue scale (VAS), (1-10 cm) at time points 0, 6, 12, 18, and 24 hr. Subjects received patient-controlled-analgesia (fentanyl 1.0 μg·kg-1 subject activated dose). Total fentanyl consumption in each group was recorded. Results: Subjects of pre-incision and post-incision groups had lower VAS scores at all time points (3.1 ± 1.8, 2.9 ± 1.3, 2.8 ± 1.3, 2.5 ± 0.9, 2.5 ± 1.5 and 3.6 ± 1.1, 3.0 ± 1.2, 3.2 ± 1.1, 2.9 ± 1.0, 2.6 ± 2.2) compared to placebo group (6.6 ± 1.3, 5.0 ± 1.0, 4.4 ± 0.7, 4.2 ± 0.8, 3.9 ± 1.0). They also used less fentanyl (563.3 μg ± 252.8 and 624.0 μg ± 210.5 respectively) compared to placebo (924.7 μg ± 417.5), (P < 0.05). No difference in total fentanyl consumption and pain scores at any time points were observed between pre- and post-incision groups. Conclusion: Pre-incision administration of 600 mg gabapentin has no added benefit over post-incision administration in terms of pain scores and fentanyl consumption in subjects undergoing open donor nephrectomy.