How do local anesthetics block nerve function?
Local anesthetics block voltage-gated sodium channels, thereby interrupting the initiation and propagation of action potential in axons. Based on this mechanism of action, local anesthetics provide a wide variety of biologic actions, both desirable and unwanted, and have side effects through other mechanisms. In addition to blockade of the action potential, local anesthetics can inhibit various receptors, enhance release of glutamate, and depress the activity of certain intracellular signaling pathways. Toxicity may be local or systemic. The central nervous and cardiovascular systems are most commonly the targets for acute clinical toxicity caused by local anesthetics.