The cocaine molecule was used first for anesthetics means. We can imagine that the benefits were momentous in the history of surgery. It marked the passing of the traumatic, painful, dangerous, and primitive surgical methods to the painless surgery of the future. 

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 effect, we now know was produced by the following mechanism: The membrane of the axon (nerve trunk) is formed by a bimolecular layer of lipids, which possess hydrophilic protein layers on both sides. The local anesthetic is linked by its hydrophilic portion to the corresponding receiver of the nerve membrane and by its lipophilic portion to the other. This changes the properties of the conductor nerve membrane blocking the sodium ions and altering the capacity of depolarization of the axon membrane, which is the mechanism through which the nerve conduction is produced. 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. With greater concentrations of the drug, the sensitivity to heat and cold at first, and then the sensitivity to tact and pressure are also blocked. Very high concentrations will even impede motor impulses. The assimilation of the drug into the blood stream can also produce systemic or general analgesic effects.