Why is there epinephrine in local anesthetic?


I have been told it makes the local last longer. I don’t understand how when epi speeds heart rate and I assume metabolism.

In: 3

From what I’ve been able to gather, since epinephrine is a stimulant, it causes blood vessels to contract, reducing flow in the area. Since anesthesia causes vessels to dilate, this is necessary to keep the anesthetic local and prevent it from getting places it’s not meant to

If I don’t get ephedrine in my local (I ask for it without at the dentist as taking Adderall and mixing any other stimulant with it makes me ill and found this out the hard way during a filling) is there a heightened chance of any risks? It honesty seems like it doesn’t work as well or last as long but I’m talking more serious.