Optimal dosing of preoperative gabapentin for prevention of postoperative nausea and vomiting after abdominal laparoscopic surgery: A randomized prospective comparative study

Background: Gabapentin has great efficacy in the treatment of neuropathic pain as a non-opioid alternative. It has been reported to prevent nausea and vomiting postoperatively. Our study compared different dosing regimens to evaluate their effectiveness and frequency of side effects in patients scheduled for laparoscopic abdominal surgery.Methods: 150 adult patients scheduled for elective abdominal laparoscopic surgery were randomly assigned to three equal groups. Group G300 received 300 mg gabapentin orally 1 h before surgery. Group G600 received 600 mg gabapentin orally 1 h before surgery. Group G900 received 900 mg gabapentin orally 1 h before surgery. Incidence and severity of PONV, need for rescue antiemetics, need for rescue analgesia, and incidence of side effects were assessed.Results: Incidence and severity of PONV were statistically higher in G300 versus G600, and G900 (8/50, 4/50, 3/50, respectively) and the total number of patients who received antiemetics, the overall dose of given granisetron, VAS scores for pain, and the total required rescue analgesia were higher in G300 versus G600, and G900. The time needed for first rescue analgesia was statistically longer in G600 and G900 versus G300. G900 was associated with a higher incidence of somnolence/sedation and dry mouth than G300 and G600.Conclusion: Gabapentin 600 mg administered 1 hr before laparoscopic abdominal surgery is as effective as gabapentin 900 mg for PONV control and VAS reduction of 24-hour postoperative pain scores with fewer side effects. On the other hand, gabapentin 300 mg did not demonstrate good control of PONV, or pain control compared to higher doses.