Local anesthesia is used to block pain in a specific part of your body, allowing you to remain fully alert. The area that is anesthetized is usually small and superficial. For local anesthesia, an anesthetic is injected at or near the site of the procedure. The injection numbs the area to pain and any other sensation. Local anesthetics are generally of short duration. They come in different forms, including injections, sprays and ointments. Only rarely do they cause an allergic reaction. A local anesthetic is used for dental work, skin biopsies or stitching up a cut. Sometimes a local anesthetic is used for a more extensive procedure in people for whom general or regional anesthesia is inadvisable. Local anesthesia with sedation offers anesthesia personnel and the surgeon great flexibility in tailoring the degree of anesthesia to the needs of the patient. The Procedures that once required patients to stay overnight in the hospital are now performed safely in outpatient surgical suites. The introduction of new anesthetic applications enables patients to undergo lengthy and complex procedures as outpatients and then promptly and safely be discharged home. Complications of local anesthetic agents can manifest as a localized reaction or systemic adverse effects. Cardiovascular disease, hepatic and renal dysfunction, acid-base abnormalities, and hypoxia can amplify the possibility of anesthetic toxicity. In addition, the very old, very young, and gravid females may respond aberrantly to these agents. Localized untoward effects include prolonged or permanent paresthesias, anesthesia, and motor weakness. In addition, local vasoconstriction has been reported with resultant necrosis. Systemic adverse effects can result in angina pectoris, shortness of breath, dysrhythmias, and cardiovascular collapse. Bupivacaine in particular has been associated with decreased cardiac output and hypotension. Disorientation, auditory and visual hallucinations, and decreased responsiveness, including coma, are possible effects of central nervous system toxicity. Respiratory and cardiovascular collapse and seizures also may emanate from central nervous system induced toxicity.