Gabapentin治療帶狀皰疹後神經痛的起始劑量——一個藥物劑量反應研究

Starting Dose of Gabapentin for Patients with Post-herpetic Neuralgia — A Dose-response Study

背景：許多研究顯示，gabapentin可用於治療帶狀皰奢後神經痛，在每天1200 mg至2400 mg的 劑量下，可以提供最大的止痛效果，然而起始劑量的使用，並沒有相關的研究。本篇的研究 目的，在於建立治療帶狀皰參後神經痛的起始劑量。方法：這是一個臨床隨機時序性的研究，將病人隨機分成三組5分別接受每天200 mg、400 mg或600 mg的gabapentin連續三天。分別在第0天與第3天評估止痛效果以及眩暈、欲睡和疲倦等副作用。結果：總共有61位病人參與研究計畫，32位男性29位女性。在三天的治療後，三組病人的疼 痛都有獲得改善（P< 0.05） 。副作用方面，接受不同劑量的三組病人，眩暈、欲睡和疲倦的程 度並沒有差異（P>0.05）。結論：研究結果顯示在前三天的治療，接受gabapentin200mg、400mg或600mg的病人，疼痛都 有相當的減緩與最少的副作用。所以，每天200 mg的最低起始劑量，並不能提供減少副作用 的效果時，我們建議以gabepentin每天600 mg的起始劑量，可以安全有效的使用於病人上。

Background: Gabapentin has been shown to provide pain relief for post-herpetic neuralgia at dosage of 1,200 to 2,400 mg/day. However, the initial dosing strategy has not been thoroughly investigated. The purpose of this study was to establish the initial dosing strategy in the treatment of the gabapentin-naive patients with post-herpe-tic neuralgia. Methods: This clinical study was an open-label, randomized, time-sequence and controlled trial. Each gaba- pentin-naive subject was allocated to receive either 200 mg (100 mg, twice daily), 400 mg (100 mg, four times daily), or 600 mg (200 mg, three times daily) of gabapentin for three days. The analgesic effect and occurrence of dizziness, drowsiness, and fatigue were assessed at day 0 and day 3. Results: A total of 61 subjects (32 male/29 female) were enrolled in this study. The intensity of pain was greatly improved in all three groups after three days of treatment (visual analog scale decreased from 6.5 士 1.6 to 4.5 士 2.1, P < 0.05). There was no statistically significant difference among subjects taking 200 mg, 400 mg, or 600 mg with respect to dizziness, drowsiness or fatigue. Conclusions: This study shows that elderly gabapentin-naive subjects no matter whether receiving 200, 400 or 600 mg/day of gabapentin benefited a moderate pain relief with minimal side effects at the first three days of treat-ment. Since starting with a minimal dose of 200 mg/day did not offer a better reduction of side effects, we suggest that 600 mg/day gabapentin could be a safe and effective starting dose for patients with post-herpetic neuralgia.