Local anesthetics are commonly used medicines in clinical settings. They are used for pain management during minor interventional treatments, and for postoperative care after major surgeries. Cocaine is the well-known origin of local anesthetics, and the drug and related derivatives have long history of clinical usage for more than several centuries. Although illegal use of cocaine and its abuse are social problem in some countries, other local anesthetics are safely and effectively used in clinics and hospitals all over the world. However, still this drug category has several side-effects and possibilities of rare but serious complications. Acute neurotoxicity and cardiac toxicity are derived from unexpected high serum concentration. Allergic reactions are observed in some cases, especially following the use of ester structure drugs. Chronic toxicity is provoked when nerve fibers are exposed to local anesthetics at a high concentration for a long duration. Adequate treatments for acute toxic reactions can secure complete recovery of patients, and careful use of drugs prevents long-lasting neurological complications. In addition to respiratory and circulatory management, effectiveness of lipid rescue in the acute toxicity treatment has been certified in many clinical guidelines. Prevention of the use of high concentration of local anesthetics is also validated to be effective to decrease the possibility of nerve fiber damage.
Mechanisms and symptoms of acute local anesthetic toxicity.