Local anesthetics: Review of pharmacological considerations

Local anesthetics have an impressive history of efficacy and safety in medical and dental practice. Their use is so routine, and adverse effects are so infrequent, that providers may understandably overlook many of their pharmacotherapeutic prin-ciples. The purpose of this continuing education article is to provide a review and update of essential pharmacology for the various local anesthetic formulations in current use. Technical considerations will be addressed in a subsequent article. Key Words: Local anesthetics; Pharmacology; Drug toxicity; Dentistry. Local anesthetics interrupt neural conduction by in-hibiting the influx of sodium ions through chan-nels or ionophores within neuronal membranes. Nor-mally these channels exist in a resting state, during which sodium ions are denied entry.When the neuron is stimulated, the channel assumes an activated or open state, in which sodium ions diffuse into the cell, initiating depolarization. Following this sudden change in membrane voltage, the sodium channel assumes a