When the substance was applied to a nerve trunk, it either blocked or reversibly interrupted the passage of nervous impulses which transmit the sensation of pain to the nerve centers of the brain, and more importantly, without loss of consciousness.

This peculiarity, since called the local anesthetic effec. By preventing the passage of sodium ions, local anesthetics such as cocaine and its synthetic derivatives, also inhibit the conduction of nerve impulses which transmit the pain sensation to the brain.