a very short half-life you get rid of very quickly.

很短的半衰期则说明你可以很快的清除它
What's the result of that?

这说明什么
That for drugs with a short half-life,

短半衰期的药物
drugs that the body gets rid of more rapidly,

会更快地被机体清除
if the desired effect isn't

如果一次注射没有达到预期效果
achieved with one dose I have to give another dose.

我们只能再一次给药
I'd have to give another

我只好再一次给药
dose if the drug had a half-life of six minutes,

如果这种药的半衰期只有六分钟
I'd have to give another dose when the drug concentration dropped

当它的浓度下降到相当低的水平时
down to a very low level

我们只能再一次给药
if I want to maintain a high concentration.

为了维持我们想要保持的高浓度
Knowing the half-life is really important and when you--

记住半衰期是很重要的