临床药师要关注药物的代谢转化

药物进入体内后，经有关酶的催化，进行化学变化，称代谢转化。药物经转化后水溶性增高，有利于排泄体外。多数情况代谢产物的活性或毒性降低，但也有不少实例经代谢转化后代谢产物药理活性或毒性增高。药物的酶促代谢不只通过单一途径，产生的也不仅单一产物，每个代谢产物的药理活性或毒性不同，而每个病人的酶活性有所不同，对通过这些途径的速率相异，可表现为药物效应或毒性的个体差异。临床药师观察到病人所表现的不同反应往往可用代谢转化的观点解释，因而临床药师要关注药物的代谢转化，以便协助医师更适当、更安全有效地用药。

Clinical pharmacists should pay more attention to drug metabolism and transformation

As drugs are foreign to the natural endogenous body substrate, the body often tries to render the drugs to leave the body by means of metabolic transformation, which involves the conversion of relatively nonpolar lipophilic compounds into more hydrophilic compounds. The later can then be readily excreted. Some types of chemical reactions such as oxidation, reduction, conjugation, etc. are involved in the course of metabolic transformation. Most of drugs are transformed in the body into inactive metabolites. Consequently, an increase in the drug metabolism rate will decrease the potency and duration of action of such drugs, and a decrease in the rate of drug metabolism will increase the intensity and duration of action of the drug. Numerous other drugs produce metabolites even more active pharmacologically, and even more toxic than the drug administered. Sometimes, drug metabolism involves more than one chemical pathway and therefore more than one metabolites. Each metabolite may exhibit different pharmacological activity. The rate of the reaction may vary markedly with different subjects. An individual variation in the intensity and duration of action may occur with different subjects. Most events observed in patients may be explained by the knowledge of metabolic transformation. Metabolic data have become increasing requirement for clinical pharmacists in order to assist the physicians to use drugs properly, safely and effectively.