Use

This Class 1B drug is used to suppress premature ventricular arrhythmias and may be as effective as quinidine or procainamide for this purpose. Mexiletine is less effective in patients with recurrent refractory ventricular tachycardia and fibrillation, and extracardiac side effects may limit its long-term usefulness. Approximately 45% of all patients experience side effects within the commonly accepted therapeutic range of 0.5−2.0 μg/mL.1 Concurrent administration of a Class 1A antiarrhythmic drug (eg, quinidine, disopyramide) or propranolol may provide better control of the arrhythmia and permit a reduction in the dose of mexiletine, thus reducing side effects. Supraventricular arrhythmias are not controlled by mexiletine.