Gabapentin Does Not Reduce Preoperative Anxiety When Given Prior to Total Hip Arthroplasty

Introduction. Gabapentin is an anti-epileptic drug which is also used for the treatment of postoperative pain and a variety of psychiatric diseases including chronic anxiety disorders. We tested the hypothesis that compared with a placebo control, gabapentin would reduce preoperative anxiety in patients undergoing total hip arthroplasty. Methods. Following ethics approval, patients participating in a larger double blind, randomized, trial of multimodal analgesia were given either gabapentin 600 mg (N = 22) or placebo (N = 48) 2 hours before spinal anesthesia. Prior to administering the study medication, baseline anxiety levels were measured using a visual analog scale (VAS). Two hours after the ingestion of gabapentin or placebo, and prior to surgery, patients again rated their anxiety using a VAS. Results. Anxiety scores did not differ significantly between the groups either before (P = 0.95) or 2 hours after (P = 0.61) ingestion of gabapentin or placebo. Baseline anxiety and postdrug anxiety scores failed to demonstrate a significant association with maximal postoperative pain at rest, maximal postoperative pain with movement, and cumulative morphine consumption 48 hours after surgery. Conclusions. Administration of gabapentin 600 mg prior to surgery does not reduce preoperative anxiety.