Article Sections

Introduction

Local anesthetics temporarily block pain perception in a targeted area without impairing consciousness.  They work by inhibiting voltage-gated sodium channels in nerve cell membranes, thereby halting the transmission of sensory signals to the brain.  Local anesthetics have a wide range of clinical uses, from alleviating pain during minor procedures to providing regional anesthesia.  They are classified into 2 categories (amides and esters) based on their chemical structure, metabolism, and clinical characteristics.

Mechanism of action

Nerve impulses are transmitted by the rapid influx of sodium ions through voltage-gated sodium channels in neuronal membranes.  Local anesthetics reversibly block these voltage-gated sodium channels, preventing depolarization and halting the propagation of action potentials.  This interrupts the transmission of pain signals to the brain.  Sensory blockade occurs in a predictable sequence, beginning with the loss of pain perception, then temperature, touch, and pressure.

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