Lidocaine

Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic of the amino amide type.^[11] It is also used to treat ventricular tachycardia and ventricular fibrillation.^[8][9] 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.^[9][10] Lidocaine mixtures may also be applied directly to the skin or mucous membranes to numb the area.^[11][9] It is often used mixed with a small amount of adrenaline (epinephrine) to prolong its local effects and to decrease bleeding.^[9]

If injected intravenously, it may cause cerebral effects such as confusion, changes in vision, numbness, tingling, and vomiting.^[11][8] It can cause low blood pressure and an irregular heart rate.^[8] There are concerns that injecting it into a joint can cause problems with the cartilage.^[9] It appears to be generally safe for use in pregnancy.^[8] A lower dose may be required in those with liver problems.^[8] It is generally safe to use in those allergic to tetracaine or benzocaine.^[9] Lidocaine is an antiarrhythmic medication of the class Ib type.^[8] This means it works by blocking sodium channels thus decreasing the rate of contractions of the heart.^[11][8] When injected near nerves, the nerves cannot conduct signals to or from the brain.^[9]

Lidocaine was discovered in 1946 and went on sale in 1948.^[12] It is on the World Health Organization's List of Essential Medicines.^[13] It is available as a generic medication.^[9][14] In 2022, it was the 262nd most commonly prescribed medication in the United States, with more than 1 million prescriptions.^[15][16]