Lidocaine is one of the most commonly used local anesthetics and may also be used in the treatment of arhythmia and serious skin irritation. It is used in both medicine and dentistry. It was developed in 1943 and first marketed in 1949. Its primary benefits as a local anesthetic are its rapid action (initially within seconds with full effect within minutes) and it's intermediate duration, wearing off within a few hours. When used as an anesthetic, lidocaine is usually injected into the skin or muscle. However, for other uses, it is available as a pill, liquid or patch.