随着社会对合理用药的日益重视,药物临床研究的范围不断扩大,药物立体化学已经作为临床药理不可缺少的基础知识出现于医药文献。具有手性中心的药物有光学异构体,按其对偏振光的旋转方向不同而分为右旋体(+)和左旋体(一);按其药理活性相对强弱又可分为高活性异构体和低活性异构体。由于技术原因,过去临床使用的合成药物常为外消旋体(±)。近年研究表明,不能把低活性异构体简单地看作无关疗效的成分;而要具体分析光学异构体的药效和毒副作用。鉴于后者与临床合理用药密切相关,本文按选用不同异构体的原因加以分类并例举应用于后。副反应因低活性异构体有副反应,而用高活性异构体。氯胺酮:麻醉药(±)氨胺酮(1,Ketamine),虽无抑制呼吸作用,但有不良反应,如部分病人手术后呈现不安定、失去自控能力,激动好斗或定向 With the increasing social attention to rational drug use, the scope of drug clinical research continues to expand. The stereochemistry of drugs has emerged as an indispensable basic knowledge in clinical pharmacology in the medical literature. Drugs that have a chiral center have optical isomers, which are divided into dextrorotary (+) and levorotatory (a) according to their different directions of rotation of the polarized light. According to the relative strength of their pharmacological activities, they can be divided into high activity Isomers and low activity isomers. For technical reasons, the past clinical use of synthetic drugs often racemic (±). In recent years, studies have shown that low activity isomers can not be simply regarded as irrelevant components of the efficacy; but to specific analysis of the optical isomer efficacy and side effects. In view of the latter is closely related with clinical rational use of drugs, this article according to the reasons for the selection of different isomers to be classified and cited as applied to the post. Side effects due to low activity isomers side effects, but with high activity isomers. Ketamine: (±) Ketamine (1) Ketamine, although no respiratory effects, but adverse reactions, such as some patients showed unstable after surgery, loss of self-control ability, agitation or aggressive