synthetic organic compound used in medicine, usually in the form of its hydrochloride salt, as a local anesthetic. Lidocaine produces prompter, more intense, and longer lasting anesthesia than does procaine (Novocaine). It is widely used for infiltration, nerve-block, and spinal anesthesia in a 0.5 to 2 percent aqueous or saline solution and is also applied to mucous membranes (2 to 4 percent) for mucosal anesthesia.