Mexiletine is used to treat certain types of ventricular arrhythmias (abnormal heart rhythms) with QT prolongation.
How it works
Mexiletine is a local anesthetic and antiarrhythmic (Class IB) agent structurally related to lidocaine. Mexiletine exerts its antiarrhythmic effect by inhibiting the inward sodium current in cardiac cells, thereby reducing the rate of rise of the cardiac action potential (phase 0) and decreases automaticity in the Purkinje fibers. This slows nerve impulses in the heart and stabilizes the heartbeat. Mexiletine’s anesthetic activity is due to its ability to block sodium influx in peripheral nerves, thereby reducing the rate and intensity of pain impulses reaching the central nervous system.
Indications
Mexiletine is used to treat certain types of ventricular arrhythmias (abnormal heart rhythms) with QT prolongation.
Dosage
The dosage of mexiletine hydrochloride must be individualized on the basis of response and tolerance, both of which are dose-related. Administration with food or antacid is recommended. Initiate therapy with 200 mg every eight hours when rapid control of arrhythmia is not essential. A minimum of two to three days between dose adjustments is recommended. Dose may be adjusted in 50 or 100 mg increments up or down.
Side Effects
Nausea, vomiting, heartburn, dizziness, lightheadedness, vision problems (such as blurred vision), headache, shaking, nervousness, or problems with muscle control (coordination difficulties) may occur.
Contraindication
Mexiletine hydrochloride is contraindicated in the presence of cardiogenic shock or pre-existing second- or third-degree AV block (if no pacemaker is present).