Toxic Effects of Local Anesthetics

LOCAL anesthetics are among the most widely used drugs in medical and dental practice; systemic toxic reactions thus may be expected on occasion. As these drugs have found some new applications of late, their toxic effects warrant review—all the more because improved methods of preventing and treating unwanted side effects have become available. This communication describes why a locally injected drug can produce reactions in distant organ systems and what the common symptoms are; it shows ways to minimize the incidence of side effects and, finally, suggests how to treat reactions. Until recent years, local anesthetics were used primarily to numb circumscribed parts of the body by injecting the drug close to spinal roots or peripheral nerve, or by infiltrating it near cutaneous nerve endings. Though some of the drug reaches its intended neural target (there to block impulse conduction), much of the perineurally injected anesthetic falls short of the