Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic of the amino amide type. It is also used to treat ventricular tachycardia. When used for local anaesthesia or in nerve blocks, lidocaine typically begins working within several minutes and lasts for half an hour to three hours. Lidocaine mixtures may also be applied directly to the skin or mucous membranes to numb the area. It is often used mixed with a small amount of adrenaline (epinephrine) to prolong its local effects and to decrease bleeding.If injected intravenously, it may cause cerebral effects such as confusion, changes in vision, numbness, tingling, and vomiting. It can cause low blood pressure and an irregular heart rate. There are concerns that injecting it into a joint can cause problems with the cartilage. It appears to be generally safe for use in pregnancy. A lower dose may be required in those with liver problems. It is generally safe to use in those allergic to tetracaine or benzocaine. Lidocaine is an antiarrhythmic medication of the class Ib type. This means it works by blocking sodium channels and thus decreasing the rate of contractions of the heart. When injected near nerves, the nerves cannot conduct signals to or from the brain.Lidocaine was discovered in 1946 and went on sale in 1948. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication.
It is used as an adjuvant, adulterant, and diluent to street drugs such as cocaine and heroin. It is one of the three common ingredients in site enhancement oil used by bodybuilders. Adulterant in cocaine
Lidocaine is often added to cocaine as a diluent. Cocaine and lidocaine both numb the gums when applied. This gives the user the impression of high-quality cocaine, when in actuality the user is receiving a diluted product. Compendial status
Japanese Pharmacopoeia 15
United States Pharmacopeia 31

Veterinary use
It is a component of the veterinary drug Tributame along with embutramide and chloroquine used to carry out euthanasia on horses and dogs. See also
Dimethocaine (has some DRI activity)
Lidocaine/prilocaine
Procaine
Mexiletine

References
External links
"Lidocaine". Drug Information Portal. U.S. National Library of Medicine. "Lidocaine Transdermal Patch". MedlinePlus. US patent 2441498, Nils Magnus Loefgren & Bengt Josef Lundqvist, "Alkyl glycinanilides", published 1948-05-11, issued 1948-05-11,  assigned to ASTRA APOTEKARNES KEM FAB