Reaction to local anesthesia can be varied in extent and severity. However, most reactions are a result of either the local anesthetic agent itself or the vasoconstrictor within the formulation. Although today's local anesthetics have a wide therapeutic index, toxicity can occur-most commonly from rapid intravascular injection. Reactions to local anesthetics can occur as quickly as 30 to 60 seconds or as slowly as 1 hour after injection. Local anesthetic dosing should be calculated based on the patient's physical condition and body weight (see dosing guidelines table in Section IV).

SIGNS & SYMPTOMS OF LOCAL ANESTHETIC TOXICITY