The efficacy of intravenous mexiletine on ventricular ectopic activity.

Twelve patients with severe ventricular dysrhythmias were treated by one single dose of 250 mg of mexiletine injected intravenously over a 15 min. period. All patients showed some antiarrhythmic response. In 9 cases, the ventricular premature beats were totally or almost totally abolished up to 20 to 100 min. after the end of the infection. In most patients (5/7), there existed a correlation between the plasma concentration of the drug and the antiarrhymic action. However, the drug levels were not different in the good responders as compared to the poor responders or in those who manifested a prolonged antiarrhythmic activity as compared to the others. Side-effect appeared in three cases and consisted of vomiting, tremor, and episodes of sinus arrest.