pharmacopeia
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/api/v1/drug/mexiletine

Mechanism of action

Sourced from openFDA

Mechanism-of-action class: Sodium Channel Interactions.

Indications

Sourced from openFDA
  • Mexiletine hydrochloride capsules, USP are indicated for the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that, in the judgment of the physician, are life-threatening. Because of the proarrhythmic effects of mexiletine, its use with lesser arrhythmias is generally not recommended.

Contraindications

Sourced from openFDA
  • Mexiletine hydrochloride capsules are contraindicated in the presence of cardiogenic shock or preexisting second- or third-degree AV block (if no pacemaker is present).contraindicated

Dosage & administration

Sourced from openFDA

The dosage of mexiletine hydrochloride must be individualized on the basis of response and tolerance, both of which are dose-related. Administration with food or antacid is recommended. Initiate mexiletine therapy with 200 mg every eight hours when rapid control of arrhythmia is not essential. A minimum of two to three days between dose adjustments is recommended. Dose may be adjusted in 50 or 100 mg increments up or down. As with any antiarrhythmic drug, clinical and electrocardiographic evaluation (including Holter monitoring if necessary for evaluation) are needed to determine whether the desired antiarrhythmic effect has been obtained and to guide titration and dose adjustment. Satisfactory control can be achieved in most patients by 200 to 300 mg given every eight hours with food or antacid. If satisfactory response has not been achieved at 300 mg q8h, and the patient tolerates mexiletine well, a dose of 400 mg q8h may be tried. As the severity of CNS side effects increases with total daily dose, the dose should not exceed 1200 mg/day. In general, patients with renal failure will require the usual doses of mexiletine hydrochloride. Patients with severe liver disease, however, may require lower doses and must be monitored closely. Similarly, marked right-sided congestive heart failure can reduce hepatic metabolism and reduce the needed dose. Plasma level may also be affected by certain concomitant drugs (see PRECAUTIONS, Drug Interactions ).

Warnings & precautions

Sourced from openFDA

BOXED WARNING WARNINGS Mortality In the National Heart, Lung and Blood Institute’s Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multicentered, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction more than six days but less than two years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3%). The average duration of treatment with encainide or flecainide in this study was ten months. The applicability of the CAST results to other populations (e.g., those without recent myocardial infarction) is uncertain. Considering the known proarrhythmic properties of mexiletine and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of mexiletine as well as other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmia. Acute Liver Injury In postmarketing experience abnormal liver function tests have been reported, some in the first few weeks of therapy with mexiletine hydrochloride. Most of these have been observed in the setting of congestive heart failure or ischemia and their relationship to mexiletine hydrochloride has not been established.

Adverse reactions

Sourced from openFDA

Mexiletine hydrochloride commonly produces reversible gastrointestinal and nervous system adverse reactions but is otherwise well tolerated. Mexiletine has been evaluated in 483 patients in one month and three month controlled studies and in over 10,000 patients in a large compassionate use program. Dosages in the controlled studies ranged from 600 to 1200 mg/day; some patients (8%) in the compassionate use program were treated with higher daily doses (1600 to 3200 mg/day). In the three month controlled trials comparing mexiletine to quinidine, procainamide and disopyramide, the most frequent adverse reactions were upper gastrointestinal distress (41%), lightheadedness (10.5%), tremor (12.6%) and coordination difficulties (10.2%). Similar frequency and incidence were observed in the one month placebo-controlled trial. Although these reactions were generally not serious, and were dose-related and reversible with a reduction in dosage, by taking the drug with food or antacid or by therapy discontinuation, they led to therapy discontinuation in 40% of patients in the controlled trials. Table 1 presents the adverse events reported in the one-month placebo-controlled trial.

Overdosage

Sourced from openFDA

Clinical findings associated with mexiletine overdosage have included drowsiness, confusion, nausea, hypotension, sinus bradycardia, paresthesia, seizures, bundle branch block, AV heart block, asystole, ventricular tachyarrythmia, including ventricular fibrillation, cardiovascular collapse and coma. The lowest known dose in a fatality case was 4.4 g with postmortem serum mexiletine level of 34 to 37 mcg/mL (Jequier P. et. al., Lancet 1976: 1 (7956): 429). Patients have recovered from ingestion of 4 g to 18 g of mexiletine (Frank S. E. et. al., Am J Emerg Med 1991: 9:43-48). There is no specific antidote for mexiletine. Management of mexiletine overdosage includes general supportive measures, close observation and monitoring of vital signs. In addition, the use of pharmacologic interventions (e.g., pressor agents, atropine or anticonvulsants) or transvenous cardiac pacing is suggested, depending on the patient’s clinical condition.

Approval history

Sourced from openFDA
  • May 16, 1995ANDAANDA074377Teva
  • May 16, 1996ANDAANDA074450Ani Pharms
  • Jul 22, 2020ANDAANDA213500Crossmedika Sa
  • Jan 25, 2021ANDAANDA214352Ingenus Pharms Llc
  • Oct 1, 2021ANDAANDA214089Senores Pharms
  • May 25, 2022ANDAANDA202111Hospira
  • Aug 26, 2022ANDAANDA215315Rising
  • Nov 9, 2022ANDAANDA216463Annora Pharma

FAERS reports

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Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
414 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Drug Ineffective4210%
  2. 2Fatigue327.7%
  3. 3Ventricular Tachycardia317.5%
  4. 4Dyspnoea276.5%
  5. 5Nausea245.8%
  6. 6Poor Quality Sleep245.8%
  7. 7Impaired Work Ability235.6%
  8. 8Impaired Quality Of Life225.3%
  9. 9Pyrexia225.3%
  10. 10Pneumonia194.6%
  11. 11Cardiac Failure184.3%
  12. 12Hypertension184.3%
  13. 13Contusion153.6%
  14. 14Alanine Aminotransferase Increased143.4%
  15. 15Cardiac Failure Congestive143.4%

Literature

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Recent PubMed references pinned to Mexiletine as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

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The 10 most recently updated of 34 ClinicalTrials.gov registrations naming Mexiletine as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Frequently asked questions

How does Mexiletine work?
Mechanism-of-action class: Sodium Channel Interactions.
What is Mexiletine used for?
According to FDA labeling, Mexiletine carries indications including: Mexiletine hydrochloride capsules, USP are indicated for the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that, in the judgment of the physician, are life-threatening. Because of the proarrhythmic effects of mexiletine, its use with lesser arrhythmias is generally not recommended.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Mexiletine?
Mexiletine is classified as Antiarrhythmics, class Ib, Antiarrhythmic, Sodium Channel Interactions, Cardiac Rhythm Alteration.
What are the contraindications for Mexiletine?
Mexiletine labeling lists contraindications including: Mexiletine hydrochloride capsules are contraindicated in the presence of cardiogenic shock or preexisting second- or third-degree AV block (if no pacemaker is present).. Always consult the full prescribing information and a clinician.
Note. Data for mexiletine is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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