ABSTRACT
I. INTRODUCTION Anesthetic agents have been employed for many years, their introduction probably occurred in the 1840s (Gilman et al., 1985). There are three main types of anesthetics: general inhalation anesthetics, often administered in association with intravenous ones; and local anesthetics (Hardman and Limbrid, 1996). The inhalational agents in wide use are nitrous oxide, halothane, and several flurane compounds. The use of intravenous drugs adds flexibility and permits the administration of lower doses of the inhalational agents. Barbiturates, benzodiazepines, opioids, α-adrenergic agonists, used also for this purpose are considered in other sections of this work under their more usual therapeutic use; only several are included here. Lastly, the local anesthetics prevent or relieve pain by interrupting nerve conduction; lidocaine is the most widely used local anesthetic.
