Cocaine was the first recognized local anesthetic agent (LA). Its addictive properties and toxicity, i.e., psychological and physical dependence, mood alteration, CNS and cardiac excitation, and intense vasoconstriction preclude its clinical use.1 Procaine, a cocaine analog, has short duration of action, high allergenicity, and is no longer available in dental cartridges. Today, LAs available in dental cartridges include lidocaine mepivacaine, prilocaine, articaine, and bupivacaine.

LAs consist of an aromatic group connected by an ester- or an amide-linkage to an aliphatic chain with a secondary or a tertiary amine group (Figure 1).2-10 Procaine has an ester-linkage connecting the aromatic group to the amine group and is the prototypical ester or aminoester LA. Agents primarily used by dentists have an amide-linkage and lidocaine is the prototypical amide or aminoamide LA. These structural domains affect LAs pharmacological characteristics.2-10

Figure 1. Structural Domains of Local Anesthetic Agents.
Diagrams showing the structural domains of local anesthetic agents. chat Let's get started!