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Mexiletine Dosage

Applies to the following strengths: 150 mg; 200 mg; 250 mg

The information at is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Ventricular Tachycardia

Initial dose: 200 mg orally every 8 hours when rapid control of arrhythmia is not essential.
A minimum of 2-3 days between dose adjustments is recommended.
Dose may be adjusted in 50 or 100 mg increments up or down.

Usual Pediatric Dose for Arrhythmias

1.4 to 5 mg/kg/dose given every 8 hours. Begin with lower initial dosages and titrate to desired effects and serum concentrations.

Renal Dose Adjustments

No adjustment recommended

Liver Dose Adjustments

Patients with severe liver disease may require lower doses and must be monitored closely.

Dose Adjustments

Satisfactory control can be achieved in most patients by 200 to 300 mg given orally every 8 hours with food or antacid. If satisfactory response has not been achieved at 300 mg every 8 hours, a dose of 400 mg every 8 hours may be tried.
When rapid control of ventricular arrhythmia is essential, an initial loading dose of 400 mg of mexiletine may be administered, followed by a 200 mg dose in eight hours.


Marked right-sided congestive heart failure can reduce hepatic metabolism and reduce the needed dose.


Data not available

Other Comments

As the severity of CNS side effects increases with total daily dose, the dose should not exceed 1200 mg/day.
If adequate suppression is achieved on a dose of 300 mg or less every 8 hours, the same total daily dose may be given in divided doses every 12 hours while carefully monitoring the degree of suppression of ventricular ectopy. This dose may be adjusted up to a maximum of 450 mg every 12 hours to achieve the desired response.