Lidocaine is a antiarrhythmic drug commonly used to restore a regular heartbeat in patients with arrhythmia. This effect is produced both by delaying abnormal nerve pulses to the heart and reducing irritability of the heart tissue. Lidocaine is also used topically as a local anesthetic to produce numbness or loss of feeling before surgery or other painful procedures. Side effects include convulsions, anxiety, itching, and swelling.