How do local anesthetics work?
(Lansing State Journal, July 27, 1994)
When damage is done to tissue in our bodies, nerve cells are stimulated to send the message of pain to our brains. These messages are carried by small electrical currents through adjacent nerve cells. The currents are carried by ions.
For these currents to flow, the nerve cells must take up ions, such as sodium ions. Local anesthetics work by blocking the channels the sodium ions use to get into the cell. This cuts off any current and therefore any message of pain.
The effect wears off as the anesthetic diffuses throughout your body.
One of the first local anesthetics used was cocaine. Because of its addictive nature, scientists sought other local anesthetics. Many of the local anesthetics used today, such as Novocain, are chemically similar to cocaine but not addictive. This is why they end in caine.