药物半衰期(t1/2)也称血浆半衰期或残半期,含义是血液中药物浓度降低一半所需的时间(单位多用小时表示),是表示药物在体内消除速度的重要参数。当机体排泄功能正常时,大多数药物排出半量所需的时间大体是固定的,如正常人磺胺嘧啶的 t1/2为17小时,即血药浓度以0.15mg/ml降至0.075mg/ml 大致需17小时,而从0.075 Half-life (t1 / 2) is also referred to as half-life or half-life in plasma, meaning the time it takes to reduce the drug concentration in the blood by half (expressed in hours) is an important parameter that indicates the rate of drug elimination in the body. When the normal function of the body excretion, most of the time required to discharge half the amount of drugs is generally fixed, such as normal sulfadiazine t1 / 2 for 17 hours, that is, the plasma concentration of 0.15mg / ml to 0.075mg / ml roughly Takes 17 hours instead of 0.075