Mexiletine Disease Interactions

Antiarrhythmic agents can induce severe hypotension (particularly with IV administration) or induce or worsen congestive heart failure (CHF). Patients with primary cardiomyopathy or inadequately compensated CHF are at increased risk. Antiarrhythmic agents should be administered cautiously and dosage and/or frequency of administration modified in patients with hypotension or adequately compensated CHF. Alternative therapy should be considered unless these conditions are secondary to cardiac arrhythmia.

The use of mexiletine is contraindicated in patients with cardiogenic shock, second- or third-degree AV block in the absence of a functional artificial pacemaker.

Mexiletine is extensively metabolized by the liver to minimally active and inactive forms. The serum concentration of mexiletine is increased and the half-life prolonged in patients with liver impairment. Elevation of liver enzymes have been reported during the first few weeks of therapy, primarily in patients with congestive heart failure (CHF) or ischemia. Hepatic necrosis, resulting in death, has occurred. Therapy with mexiletine should be administered cautiously in patients with compromised liver function, CHF or ischemia. Clinical monitoring of cardiac function (ECG) and liver function is recommended.

Mexiletine is primarily eliminated by the kidney. Approximately 10% of mexiletine is excreted in the urine unchanged. Marked changes in urinary pH alter the rate of mexiletine excretion. Elimination is accelerated with an acidic urinary pH and slowed with an alkaline urinary pH. Therapy with mexiletine should be administered cautiously in patients with significant renal impairment. Clinical monitoring of cardiac function (ECG) and renal function is recommended.

Seizures have been reported rarely during mexiletine therapy in patients with and without a history of seizures. Therapy with mexiletine should be administered cautiously in patients with or predisposition to seizure disorders.