Lidocaine acts as a local anesthetic by reversibly blocking sodium channels and blocking the transmission of action potentials along nerve fibers. Sensory nerve fibers are blocked earlier than motor nerve fibers, so low doses of lidocaine can exert a selective sensory blocking effect. Lidocaine also has antiarrhythmic effects and belongs to class I and b antiarrhythmic drugs. It reduces ventricular rate, shortens action potential time and absolute refractory period, and prolongates relative refractory period. Lidocaine acts quickly and lasts for a short time. The addition of epinephrine to lidocaine reduces the rate of absorption throughout the body, thereby extending the duration of anesthesia.

Indication

Lidocaine is suitable for acute ventricular arrhythmias caused by acute myocardial infarction, surgery, digitalis poisoning and cardiac catheters, including ventricular premature beat, ventricular tachycardia and ventricular fibrillation. It is also used for status epilepticus.

Application:

Lidocaine is the first-line drug for the treatment of ventricular arrhythmias caused by acute and severe hemodynamic abnormalities. It is also effective for some supraventricular arrhythmias, such as bypass mediated supraventricular tachycardia and cardioversion in acute episodes or parasympathetic mediated atrial fibrillation. It is widely used for surface anesthesia of mucous membranes (e.g. before tracheal intubation). EMLA cream is used for skin surface anesthesia before intravenous catheterization. To ensure the anesthetic effect, it should be applied to the skin for 45 to 60 minutes, and wrapped with an airtight dressing to promote absorption. EMLA is very useful for ear vein catheterization in rabbits and for vein catheterization in young dogs and cats.

Drug interaction

Concurrent administration with cimetidine and propranolol will extend the serum clearance time of lidocaine. Combination with procainamine may increase CNS adverse reactions. Other antiarrhythmic agents may cause increased myocardial inhibition.