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.
Lidocaine is an amide-type local anesthetic agent and is suggested to stabilize neuronal membranes by inhibiting the ionic fluxes required for the initiation and conduction of impulses. Lidocaine blocks conduction by preventing membrane permeability to calcium-dependent sodium and potassium shifts. By stabilizing the membranes, electrical conduction is prevented. In the heart, lidocaine blocks both open and inactivated sodium channels. It decreases the slope of phase 4 depolarization and the threshold potential causing decreased myocardial automaticity. This effect is more prominent in ischemic tissue thereby synchronizing myocardial cells and making reentrant arrhythmias less likely.