Pharmacology : local anesthetics and additives

Introduction Anunderstanding of basic local anesthetic pharmacology is essential prior to safe and effective placement of any regional block. Numerous pharmacology texts and literature sources are available describing similarities and differences with regard to onset time, duration, selective motor and/or sensory blockade, tissue penetration, and toxic profile. The goal of this chapter is to provide a brief overview of the more common local anesthetics used in performing peripheral nerve blocks. To introduce the mechanism of local anesthetic action, the chapter begins with a brief review of nerve electrophysiology. A short discussion on local anesthetic structure is then covered followed by key points regarding pharmacologic properties of individual agents commonly used in peripheral nerve blocks. Local anesthetic toxicity and its management are reviewed, and the chapter concludes with a discussion of local anesthetic additives for peripheral nerve blocks.