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.