The pharmacology of local anesthetics--a review of the literature.

In the nineteenth century, some natives of Peru noticed circumoral numbness, euphoria and analgesia after chewing the leaves of the Erythroxylen coca bush. By 1850, cocaine was isolated from the plant, marking the start of the local anesthetic era in clinical medicine. Over the past 50 years, many synthetic local anesthetics have been developed which have fewer side effects, increased specificity of action and a wider margin of safety than cocaine. Currently, local anesthetics are used topically, for local infiltration; and intravenously, for peripheral nerve blockade, for sympathetic blockade, as well as for epidural and intrathecal use. Although the route of administration may affect pharmacokinetics and pharmacodynamics, it is the purpose of this article to review the general pharmacology of this entire range of clinically useful compounds.