Lidocaine hydrochloride can be used as a local anesthetic as well as an antiarrhythmic agent. It is mainly used for infiltration anesthesia, epidural anesthesia, surface anesthesia, and nerve conduction block. It is also used after acute myocardial infarction, premature ventricular beats and ventricular tachycardia, digitalis toxicity, cardiac surgery, and ventricular arrhythmias due to cardiac catheterization. In terms of dosing, surface local anesthesia is usually diluted and injected locally. If it is used to treat arrhythmias, it is usually administered intravenously by pushing or by using an infusion pump. During the course of administration, adverse reactions may occur, which may cause drowsiness, abnormal sensation, muscle tremors, convulsions, coma and respiratory depression, and in rare cases, may cause hypotension. If the blood concentration is too high, atrial conduction velocity may be slowed and atrioventricular block may occur.