Mexiletine
Also known as: Mexitil, Mexilen, Mexitilen, Myovek, Ritalmex
- **Always give with food**: This medication frequently causes stomach upset, nausea, and vomiting. Giving it with a full meal significantly reduces this risk. - **Strict Adherence**: Do not skip doses or stop the medication without consulting your veterinarian. Ventricular arrhythmias can be life-threatening and may return rapidly if the drug is discontinued. - **Monitor for Side Effects**: Contact your veterinarian immediately if your pet experiences persistent vomiting, trembling, unsteadiness, dizziness, extreme lethargy, or shortness of breath.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Treating or assisting in treatment of ventricular arrhythmias
- Treating or assisting in treatment of ventricular arrhythmias
- Ventricular arrhythmias in Boxers
- Treating or assisting in treatment of ventricular arrhythmias
- Familial arrhythmic cardiomyopathy of Boxers (ARVC)
- Treating or assisting in treatment of ventricular arrhythmias
- Myotonia congenita or myokymia
How it is given
Possible side effects
- Vomiting (very common)
- Nausea
- Trembling/Tremors
- Unsteadiness/Ataxia
- Dizziness
- Depression/Lethargy
- Shortness of breath
- Proarrhythmia (PVCs)
- Chest pain
- Seizures (rare)
- Agranulocytosis (rare)
- Thrombocytopenia (rare)
Cautions & contraindications
- Pre-existing 2nd or 3rd degree AV block (without a pacemaker)
- Cardiogenic shock
- Known hypersensitivity to mexiletine
- Use with **extreme caution** in patients with severe congestive heart failure, acute myocardial infarction, hepatic function impairment, hypotension, intraventricular conduction abnormalities, sinus node function impairment, or a pre-existing seizure disorder. > **Clinical Note**: Mexiletine is secreted into maternal milk; use of a milk replacer is recommended if the nursing mother is receiving the drug. FDA Pregnancy Category C.
Drug interactions
- Antacids (Aluminum-Magnesium): May slow the absorption of mexiletine.
- Atropine: May reduce the rate of oral absorption.
- Cimetidine: May increase or decrease mexiletine blood levels.
- Griseofulvin: May accelerate the metabolism of mexiletine.
- Lidocaine: May cause additive adverse effects (especially CNS toxicity).
- Metoclopramide: May accelerate the absorption of mexiletine.
- Opiates: May slow the absorption of mexiletine.
- Phenobarbital: May accelerate the metabolism of mexiletine.
- Primidone: May accelerate the metabolism of mexiletine.
- Phenytoin: May accelerate the metabolism of mexiletine.
- Rifampin: May accelerate the metabolism of mexiletine.
- Theophylline: Mexiletine may reduce the metabolism of theophylline, potentially leading to theophylline toxicity.
Frequently asked questions
What is Mexiletine used for in pets?
- **Always give with food**: This medication frequently causes stomach upset, nausea, and vomiting. Giving it with a full meal significantly reduces this risk. - **Strict Adherence**: Do not skip doses or stop the medication without consulting your veterinarian. Ventricular arrhythmias can be life-threatening and may return rapidly if the drug is discontinued. - **Monitor for Side Effects**: Contact your veterinarian immediately if your pet experiences persistent vomiting, trembling, unsteadiness, dizziness, extreme lethargy, or shortness of breath.
Is Mexiletine safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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