ABSTRACT
Cocaine was the first local anesthetic introduced into medical practice in 1884 by the ophthalmologist Koller, who described its use for topical anesthesia of the cornea. Subsequently it was used in local infiltration anesthesia, nerve conduction blockade and, in 1898, by Bier for spinal anesthesia. Local anesthetics block sodium channels in cell membranes. They prevent the influx of sodium ions into cells and thereby the generation of action potentials and the conduction of nerve impulses. Treatment of malignant arrhythmias caused by local anesthetic overdose should follow established guidelines for advanced cardiac life support, including early defibrillation and the use of the antiarrhythmic amiodarone. Lidocaine is the most widely used short-acting local anesthetic worldwide. Absorption can be reduced, and therefore length of action increased and the risk of toxicity decreased, by the addition of vasoconstrictors to the solution. Lidocaine is available in a number of preparations: ointments, jelly, topical solutions including a spray, and formulations for injection.
