Thesis (M.Sc.)--Chulalongkorn University, 2003

Objective : To find the efficacy of 300 mg. gabapentin given orally as single daily dose, starting preoperatively, in reduction of postoperative pain in primary TKR. Design : Randomized triple-blind controlled trial. Setting : Bangkok Metropolitans Administrator Medical College and Vajira Hospital Method : Fifty patients who schedulled for TKA was enrolled to this study, 49 patients completed the study. Patients were randomized to receive placebo or gabapentin orally preoperative and another dose at 24 hours later. All patients received morphine intravenously through PCA machine as a rescue medication. Amount of morphine consumption, and pain score during 48 hours postoperative period were recorded. Also with adverse effects and complications occurred during admission were recorded as well. Results : There was statistically significant difference in morphine consumption during first 24 hours comparing between two groups (31 mg vs 20 mg, p-value=0.008, 34% reduction). No significant difference was detected in term of morphine used in second 24 hours, pain score at any point of time, incidence of adverse effects and complications. Common adverse effect found in this study is nausea and vomitting which found in 67% of the patients. Conclusion : Oral daily dose of 300 mg gabapentin is effectively reduced postoperative pain in first 24 hours postoperative by 34% as measured by amount of morphine consumption.