How do local anaesthetics stay local for several hours instead of transferring around your body through the bloodstream?

Question

How do local anaesthetics stay local for several hours instead of transferring around your body through the bloodstream?

In: 43

Answer 1

When they inject local anesthetics, it’s usually only skin deep. The blood vessels in the skin are super tiny. Much smaller than the needle they’re using. The anesthetics just pool in a spot in the skin. Some of it does get absorbed through the small blood vessels, but the amount they typically use is so small it doesn’t affect the rest of the body.

Now, if they use a lot of anesthetics in a larger area, more of it will get absorbed and can be toxic.