<p>Lidocaine acts mainly by inhibiting sodium influx through sodium specific ion channels in the neuronal cell membrane, in particular the so called voltage-gated sodium channels. When the influx of sodium is interrupted, an action potential cannot arise and signal conduction is inhibited. The receptor site is thought to be located at the cytoplasmic (inner) portion of the sodium channel. Lidocaine binds more readily to sodium channels in activated state, thus onset of neuronal blockade is faster in neurons that are rapidly firing. This is referred to as state dependent blockade.</p>