Drug reference

Mexiletine

Antiarrhythmic · Antiarrhythmic, Skeletal Muscle Relaxant

Also known as Mexiletine hydrochloride

AntiarrhythmicAntiarrhythmic, Skeletal Muscle RelaxantATC C01BB02

CDSCO approvedSchedule HATC C01BB02

EXCRETION

—

not curated

INTERACTIONS

11 major

SEVERE in our sources

PREGNANCY

—

not curated

Top interactionssee all 12 →

AminophyllineSevereDatabaseDDInter
ArbutamineSevereDatabaseDDInter
BupropionSevereDatabaseDDInter
DofetilideSevereDatabaseDDInter

Mechanism

Mexiletine is a sodium channel blocker which reduces the delay of muscle relaxation thereby decreasing muscle stiffness. It is also classified as a Class IB antiarrhythmic, acting to control ventricular arrhythmias.

Indications

Life-threatening ventricular arrhythmiasMyotonia in non-dystrophic myotonic disordersChronic treatment to prevent ventricular tachycardiaChronic treatment to prevent ventricular fibrillationCorrecting aberrant late inward Na+ current in type 3 congenital long QT syndromePost-infarction sinister ventricular arrhythmias (parenteral, as alternative to lidocaine)Chronic suppression of ventricular extrasystoles (VES) (oral, questionable merit)Chronic suppression of ventricular tachycardia (VT) (oral, questionable merit)

Dosing

Adult: For myotonia in non-dystrophic myotonic disorders: 167 mg once daily by mouth for at least 1 week, then increased if necessary to 333 mg daily in divided doses for at least 1 week, then increased if necessary to 500 mg daily in divided doses; maintenance 167 500 mg daily.
Max dose: 500 mg per day

Pharmacokinetics

Half-life

9–15 h

Bioavailability

>80%

Protein binding

excreted in urine

Metabolism

Hepatic metabolism (inducible by phenytoin)

Contraindications

Abnormal Q-waves
Atrial tachyarrhythmia, fibrillation or flutter
Complete heart block or any heart block susceptible to evolve to complete heart block
Heart failure (with ejection fraction less than 50%)
History of myocardial infarction
Sinus node dysfunction
Symptomatic coronary artery disease
Ventricular tachyarrhythmia
Tremor

Side effects

Common

Abdominal painArrhythmiasAstheniaChest discomfortDrowsinessHeadacheHypotensionInsomniaMalaiseNauseaPain in extremityParaesthesiaSkin reactionsVasodilationVertigoVision disordersTremorVomitingDizzinessConfusionBlurred visionAtaxia

Serious