[Central toxicity of local anesthetics. New data].

The central nervous toxicity of local anaesthetics has long been thought to be limited to the generalized tonicoclonic convulsions which follow the appearance of such symptoms as sleepiness, tingling of the lips, slurred speech, numbness, etc. Also the central nervous system was considered to be more sensitive than the cardiovascular system. However, recent experimental studies would seem to indicate that at least the more potent local anaesthetics, such as bupivacaine, have deleterious effects on parts of the brain other than the cerebral hemispheres. This may point to an involvement of the central nervous system (the amygdala and vasopressor areas of the floor of the fourth ventricle) in the pathogenesis of the hypotension and arrhythmias which may be seen at the same time as central nervous system signs of systemic toxicity. This is important for the treatment of such accidents: should a convulsion occur alone, sodium thiopentone, a muscle relaxant and a benzodiazepine, with oxygen and assisted breathing, will be the treatment; should an arrhythmia occur, its treatment should also include an anticonvulsant drug, such as a benzodiazepine. The prophylactic use of benzodiazepines should also be encouraged.