Would you be unconscious if lidocaine was injected to the arm vein?

It depends on the dose. I typically give 60–100mg iv for a typical adult before induction to help decrease stimulation of the airway when we intubate the patients and also to help numb up the vein before giving Propofol which is the actual drug that “knocks” you unconscious. You generally have to apply a small tourniquette to let it sit in the vein long enough to help numb up the vein and it is of limited efficacy.

If one gives a large enough dose one can achieve toxic levels. The first sign is ringing in the ears and a metallic taste. If the concentration becomes even higher then a patient will have a seizure which basically includes loss of consciousness. The last thing that would happen at the highest doses of lidocaine would be an arrhythmia which can theoretically be fatal. It is more an issue with lidocaines relatives, especially bupivacaine. Bupivacaine tends to bind to he sodium receptors of the heart much more and can require the patient be placed on cardiac bypass or ECMO until the bupivacaine dissociates from the heart. I hope this helps answer your question.