Mexiletine (Oral)

Mexiletine is prescribed by doctors as long term therapy to treat ventricular arrhythmias, a condition in which the heart rhythm is abnormal, by blocking electrical impulses and stabilizing the condition.


Sold as the brand Mexitil, Mexiletine is an antiarrhythmic medication used for the treatment of serious heart rhythm irregularities. By maintaining a steady, regular heart rhythm, Mexiletine prevents this irregular rhythm that can eventually lead to blood clots, stroke or heart attack if left untreated.

Mexiletine works by inhibiting the electrical impulses that seem to be over-stimulating the heart, causing an irregular rhythm. With almost an anesthetic effect, this medication decreases the frequency of these electrical impulses, eventually causing the heart to adopt a more normal rhythm.

Prescribed primarily for the treatment of ventricular tachycardia, which is classified by a rapid beat of over 100 beats per minute, this condition can cause the heart to stop, which is a life-threatening condition requiring emergency treatment. A normal heart rhythm, once established, is 60 to 100 beats per minute.

Conditions Treated

Type Of Medication

  • Antiarrhythmic
  • Cardiac therapy
  • Cardiovascular agent

Side Effects

By affecting the electrical impulses that control the heart's rhythm, Mexiletine may also have adverse effects on health that should be reported right away, such as:

  • Rapid or irregular heart rhythm
  • Difficulty breathing
  • Convulsions
  • Chest pain
  • Elevated body temperature
  • Chills
  • Bruising or bleeding unexpectedly

Other health effects may occur but these are typically not cause for alarm and usually go away over time with use of the medication. It is good to let your doctor know you're having them, as there may be a way to ease them temporarily:

  • Dizzy, lightheaded sensations
  • Heartburn
  • Vomiting
  • Nausea
  • Nervous demeanor
  • Shaking or trembling hands
  • Unsteady walk, difficult to walk
  • Vision changes or blurriness
  • Confused demeanor
  • Constipation
  • Diarrhea
  • Headache
  • Tingling, numb fingers
  • Ringing sound in ears
  • Rash on skin
  • Speech changes or slurs
  • Insomnia
  • Fatigue
  • Muscle weakness

If you have any changes to your overall health or demeanor, inform your physician of your symptoms right away to prevent any long term damage to your health.


Take the prescribed amount of Mexiletine that your doctor has specifically written for you and do not change the frequency or duration of the treatment or size of dosage in any way. Avoid stomach upset and take this medication with a meal or with milk. You may also take an antacid that has been approved by your physician to avoid an upset stomach.

To provide a steady supply of Mexiletine to your system, thereby increasing the effectiveness on your heart rhythm, it is advised that you take the dosage at evenly spaced times during the day without missing any doses. If you are prescribed three daily doses, space them eight hours apart, for instance. If you need assistance in planning your treatment regimen, consult with your physician or nurse.

The capsule form of Mexiletine will typically be prescribed to adult patients with an initial dose of 200 milligrams to be taken every eight hours. This dose will be adjusted up or down depending on how effective it is on your condition.

Try to take your doses at the same time every day for the best effectiveness and to make sure you remember each dose. Should you miss a dose accidentally, it is best to skip it and continue on to the next dose rather than take a double dose of the medication and possibly cause adverse health symptoms. If you have any questions about missing a dose, get in touch with your doctor.


If you have had a prescription of this medication in the past and were sensitive to it, you should let your doctor know this information. Any reactions to other medications, animals, foods or other substances should also be reported to your physician, as they may make up some of the capsule ingredients.

The only studies performed on this medication have been in regard to use in adult patients, so it has not been approved for use in children or in geriatric patients. While use in children is not advised, geriatric patients should be able to take Mexiletine if they have their dose adjusted for any age-related health issues they have.

Pregnant women should avoid taking Mexiletine in order to protect their unborn children, as it has been known to cause birth defects. Discuss this risk with your physician if you are pregnant and need this medication.

Women who are breastfeeding should use caution when taking this medication. Your physician may advise you to stop temporarily while you are in treatment.

Take a list of all medications you are currently taking with you to see your physician before taking this drug, as some adverse reactions to certain medications have been reported. Two medications in particular are dangerous to your health if you combine them with Mexiletine, so let your physician know if you take:

  • Vernakalant
  • Lvomethadyl

The following medications, when combined with Mexiletine, may need their dosage changed in order to provide you with treatment of both medicines. Let your physician know if you are taking:

  • Amiodarone
  • Bupropion
  • Anagrelide
  • Cobicistat
  • Clozapine
  • Disopyramide
  • Dasabuvir
  • Etravirine
  • Eltrombopag
  • Ombitasvir
  • Lidocaine
  • Paroxetine
  • Paritaprevir
  • Pixantrone
  • Pirfenidone
  • Quinidine
  • Prilocaine
  • Sotalol
  • Simeprevir
  • Tizanidine
  • Theophylline

These medications may increase your risk of certain adverse health effects if taken with Mexiletine and should be avoided. Let your doctor know if you take:

  • Rifapentine
  • Fluvoxamine
  • Ritonavir

Avoid the use of tobacco products during your Mexiletine treatment, as it can exacerbate some adverse health effects. Your physician will be able to assist you with a smoking cessation program that you can safely follow during your treatment. Discuss the use of tobacco products, the consumption of alcoholic beverages and certain foods while you are on this medication, these substances could have poor a interaction with the drug.

Patients with certain medical problems should also avoid the use of Mexiletine, as they could become worse when combined with the effects of the medication. Report your full medical history to your doctor, especially if you have:


Your prescription will arrive with a patient information leaflet that you should read and comprehend prior to taking your Mexiletine. If you don't understand something, ask your physician or your pharmacist to explain it to you.

Expect to be regularly examined by your physician while you are on this medication to determine if it is working on your symptoms or causing you to have ill health. Your physician may adjust your dosage accordingly or may find alternate forms of treatment for you.

You will be instructed to keep a card with your medical identity including Mexiletine with you or jewelry to that effect at all times in case of emergency. Your physician will instruct you on how to obtain this identification.

Before you allow any other doctor or dentist to offer you treatment, let them know that you take Mexiletine as it may affect the way certain procedures or tests operate.

Avoid operating heavy equipment, power tools or a motor vehicle while you are taking this medication until you know how it affects you. Patients have reported dizziness, lightheaded symptoms and being less alert than would be safe in these situations. Do not put yourself or others in danger, use caution before you drive while on this medication.

Patients who have other heart problems in addition to ventricular tachycardia or who have liver disease should let their doctor know of these conditions prior to taking this medication, as they could be putting themselves into a life-threatening situation with use of this drug.

Mexiletine should be avoided during pregnancy unless desperately needed, which is at the discretion of you or your physician. Avoid breastfeeding during your treatment and discuss this with your physician if you have questions.

Mexiletine and other antiarrhythmic drugs have been reported to have high occurrences of heart attack and death, especially in patients who have had a heart attack within the past 48 months. This medication has not been proven to help patients with arrhythmias live longer; it is only for use in patients who have a life-threatening arrhythmia. Discuss the risks of taking this medication with your physician.


Keep Mexiletine in the container your received it in, tightly closed and out of sight and reach of children and pets. You may store this medicine at room temperature but it should be kept away from excessive heat, light and moisture, so the bathroom is not ideal.

Unused or expired doses of Mexiletine should be disposed of in a safe way, securely away from any curious children, pets or other people. A medication donation program is a great way to dispose of medication that you are no longer taking. Contact your local pharmacy for information on programs in your area or for instructions on safe disposal.

Keeping this medication out of child-proof containers and in pill-minders or daily dose containers is not recommended. Accidental ingestion of this drug by anyone without a severe heart rhythm problem can be fatal. Always use medicine with safety caps and keep it in a location that children cannot see or reach.


Mexiletine is an antiarrhythmic heart medication that is sold as Mexitil in capsule form. Patients with a serious condition known as ventricular fibrillation are typically prescribed this drug. These patients have faster than normal heart beats, at over one hundred beats per minute. Due to rapid electronic pulses causing their hearts to beat faster than normal, these patients can experience dizziness, have difficulty breathing, experience chest pains or even seizures and loss of consciousness. This condition, if left untreated, can lead to death.

Mexiletine prescriptions control the electrical synapses that are causing the heart to beat too quickly by inhibiting nerve impulses. In controlling the heart rhythm and returning it to a normal rate, patients can typically be released from the hospital to take their dosage of the medication at home. Patients are typically prescribed three 200 milligram doses of Mexiletine per day, which can be taken with food or milk to avoid stomach upset.

Use of this medication is not approved in children or some geriatric patients with age-related health conditions. Women who are breastfeeding should only use this medication if required. Avoid Mexiletine treatment if you have liver disease or other heart conditions that could be made worse by the activity of the medication.

Alert your physician if you experience chest pain, difficulty breathing, or worsening of your symptoms. Do not take other medications with Mexiletine unless specifically approved by your doctor. Take care not to miss a dose of this medication, as a steady supply to your body is the most effective treatment. It is likely that you will receive your first dose of Mexiletine while in the hospital, which will be adjusted to control your symptoms.