Mexiletine cardiovascular effects

Cardiovascular effects If a ventricular pacemaker is operative, patients with seconder third-degree heart block may be treated with mexiletine if continuously monitored. Exercise caution in such patients or in patients with preexisting sinus node dysfunction or intraventricular conduction abnormalities. 

Overdosage with mexiletine resulted in death in two cases due to cardiovascular effects (45,46). 

Adverse reactions Minor side effects of lidocaine are drowsiness, dizziness, paresthesia, and euphoria. More serious side effects include CNS and cardiovascular effects. Tocainide and mexiletine both have a high incidence of Gl side effects (nausea and vomiting) and CNS side effects (dizziness, numbness, and paresthesias). Additionally, tocainide has a 15% incidence of rash and may cause agranulocytosis. 

Mexiletine is a class Ib antidysrhythmic drug, similar in action to lidocaine, but it can be given orally. Its adverse effects occur in up to 50% of patients (1) and withdrawal is often necessary (2). The most common adverse effects are on the cardiovascular and central nervous systems. The pharmacokinetics, clinical use, and adverse effects and interactions of mexiletine have been reviewed widely (3-8). 

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