Lidocaine, also known as xylocaine and lignocaine, is a medication used to numb tissue in a specific area and to treat ventricular tachycardia. It can also be used for nerve blocks. Lidocaine mixed with a small amount of epinephrine is available to allow larger doses to be used as numbing and to make it last longer. When used as an injectable it typically begins working within four minutes and lasts for half an hour to three hours. Lidocaine may also be applied directly to the skin for numbing.