Local anesthetic toxicity: review and case studies.

One of the very real complications possible in the use of local anesthetic agents is a relative overdose of the drug, resulting in an inordinate and potentially dangerous serum level. Even when using strict and careful technique, problems can occur. The reactions cited in the aforementioned cases were most likely the result of the accidental intravenous injection of a local anesthetic agent. Two cases were treated with anticonvulsants; one was not. In retrospect, it is possible that the seizure activity seen in Case 2 may have been prevented by an intravenous injection of benzodiazepine. A variety of currently available local anesthetic compounds has been deemed safe for common usage in the field of anesthesia. The majority of problems associated with their use stem from faulty technique, ignorance, mismanagement, or simple oversight, and are not necessarily due to any intrinsic property of the drug. Nevertheless, local anesthetics are potentially toxic and their use should be approached with knowledge of and a healthy respect for their associated complications. It should also be remembered that virtually all local anesthetic toxic reactions are preventable and treatable. Their occurrence need not necessarily result in a poor outcome.