How long will last a shot of lidocaine 1% in your body?

1-3 hours: An injection of Lidocaine will numb an area for 1-3 hours. But it stays in the body for several more hours while it is broken down by the liver and removed by the kidneys.

It really depends..: Depending on where the shot is given--i.e. Given IV during a heart-attack rescue, this only last minutes. Given in the muscle--can last up to an hour or two. Given in a joint, may last several hours. A typical shot of Lidocaine does not do much once is "spread-out" in the body. So, it is a simple question, but answering it is not so simple. Consult doc. Good luck.