Drug Groups

approved

Description

Antiarrhythmic agent pharmacologically similar to lidocaine. It may have some anticonvulsant properties. [PubChem]

Indication

For the treatment of ventricular tachycardia and symptomatic premature ventricular beats, and prevention of ventricular fibrillation.

Pharmacology

Mexiletine is a local anesthetic, antiarrhythmic agent (Class Ib), structurally similar to lidocaine, but orally active. Mexiletine has fast onset and offset kinetics, meaning that they have little or no effect at slower heart rates, and more effects at faster heart rates. It shortens the action potential duration, reduces refractoriness, and decreases Vmax in partially depolarized cells with fast response action potentials. Mexiletine either does not change the action potential duration, or decreases the action potential duration.

Toxicity

Symptoms of overdose include nausea, hypotension, sinus bradycardia, paresthesia, seizures, bundle branch block, AV heart block, asystole, ventricular tachyarrythmia, including ventricular fibrillation, cardiovascular collapse, and coma.

Affected Organisms

Biotransformation

Primarily hepatic (85%) via CYP2D6 and CYP1A2 (primarily CYP2D6).

Absorption

Well absorbed (bioavailability 90%) from the gastrointenstinal tract.

Half Life

10-12 hours

Protein Binding

50-60%

Elimination

Approximately 10% is excreted unchanged by the kidney. The urinary excretion of N-methylmexiletine in man is less than 0.5%.

Distribution

* 5 to 7 L/lg

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