Randomized controlled trial of gabapentin as an adjunct to perioperative analgesia in total hip arthroplasty patients
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PURPOSE: Gabapentin was investigated as a single-dose adjunct to morphine for postoperative pain management. The primary objective was to determine if gabapentin given preoperatively and for two days postoperatively as part of multimodal analgesia would decrease postoperative morphine consumption in patients undergoing primary total hip arthroplasty (THA). METHODS: The study group included 102 patients aged 19-90 years who were undergoing primary THA in a single joint with no contraindications to the study medications, no chronic pain syndrome, and no chronic opioid use. Intervention group patients (n = 48) received gabapentin 600 mg po preoperatively and 200 mg postoperatively on the day of surgery. They were continued on gabapentin at 200 mg three times daily for two days. Control group patients (n = 54) received placebo in a similar fashion. Preoperatively, all patients were given 30 mg of ketorolac intravenously and acetaminophen 1000 mg po. Postoperatively, they received intravenous patient-controlled analgesia with morphine, along with ketorolac 15 mg iv and acetaminophen 1000 mg po every six hours. RESULTS: The primary outcome was mean (SD) postoperative morphine consumption at 72 hr which was 55.8 (39.2) mg in the gabapentin groups vs 60.7 (37.2) mg for the control group (mean difference, -4.91 mg, 95% confidence intervals [CI]: -21.2 to 11.35; P = 0.550). There were no significant differences between the groups regarding secondary outcomes: pain scores, side effects, range of motion. Patient satisfaction on day 3 was more favourable in the placebo group. Length of hospitalization was marginally shorter in the placebo group. CONCLUSIONS: This trial indicated that gabapentin treatment had no clinically important reduction in postoperative morphine consumption at 72 hr in patients undergoing THA. Multimodal analgesia may account for the similar primary and secondary outcomes found in the groups. This trial was registered at ClinicalTrials.gov, number: NCT01307202.