商品名：Benylin and others
Centrally acting antitussive drug. Dextromethorphan shares similar chemical structure to opiates but does not affect opiate receptors and appears to directly affect cough receptor. Dextromethorphan is the d-isomer of levorphan (the l-isomer, levorphan, is an opiate with addictive properties, but the d-isomer does not). Dextromethorphan produces mild analgesia and modulates pain via its ability to act as an n-methyl D-aspartate (NMDA) antagonist, but this is unrelated to the antitussive action.
Dextromethorphan has been used for suppression of nonproductive cough. However, its efficacy for reducing cough has been questioned because of a lack of proof. Dextromethorphan also has been used as an adjunct for treating pain because of NMDA antagonism. Pharmacokinetic studies in dogs indicated that dextromethorphan does not attain effective concentrations after oral administration. Even after intravenous administration, concentrations of the parent drug and active metabolite persisted for only a short time after dosing. Therefore, routine use in dogs is not recommended until more data are a
劑量數字暫停提供：VetPro 的劑量改依 DRUGAPI 藥物資料庫對外的內容，DRUGAPI 目前不提供可直接計算的劑量。下方列出 DRUGAPI 的審查結論與劑量審查引用的來源；計算機可手動輸入劑量換算。
先核對完整產品名稱、全部有效及非有效成分、鹽型或釋放系統、標示版本、法域與核准狀態 先判斷咳嗽是否具有排痰或保護功能，並評估肺炎、心臟病、氣道疾病、異物及其他潛在原因 將犬藥動研究、貓實驗模型、動物複方標示及人用產品資料分開 先核對所有併用藥與暴露產品，特別是單胺氧化酶抑制劑、血清素相關藥物及中樞作用藥 不將研究暴露、複方錠劑方向、人用標示或舊綜述表格轉成單方犬貓劑量 不將鎮靜、嘔吐或毒理症狀在缺乏分母與情境時排列成通用不良反應頻率
DRUGAPI 劑量審查引用的獸醫官方標示（各標示只適用於其產品、物種與法域，不可互換）
依出現頻率分組；嚴重副作用獨立列出，臨床上需立即辨識。