Antiarrhythmic drugs, similar to mexiletine, have been reported to increase the risk of death or heart attack, especially in people who have had a heart attack within the past 2 years. Mexiletine may increase the chance of having arrhythmias (irregular heartbeats) and has not been proven to help people without life-threatening arrhythmias to live longer. Mexiletine should be used only to treat people with life-threatening arrhythmias.
Talk to your doctor about the risks of taking mexiletine.
Mexiletine is used to treat certain types of ventricular arrhythmias (abnormal heart rhythms). Mexiletine is in a class of medications called antiarrhythmics. It works by blocking certain electrical signals in the heart to stabilize the heart rhythm.
Mexiletine comes as a capsule to take by mouth. It is usually taken three times a day, every 8 hours. Some people may take it twice daily, every 12 hours, once their arrhythmias have been controlled with mexiletine. Mexiletine should be taken with food or an antacid to prevent stomach upset. Take mexiletine at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take mexiletine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
You will probably be hospitalized when you begin your treatment with mexiletine. Your doctor will monitor you carefully during this time and for as long as you continue to take mexiletine. Your doctor will probably start you on an average dose of mexiletine and gradually increase or decrease your dose, not more than once every 2 to 3 days.
Mexiletine controls arrhythmias but does not cure them. Continue to take mexiletine even if you feel well. Do not stop taking mexiletine without talking to your doctor. If you suddenly stop taking mexiletine, your condition may become worse.
Mexiletine is also used to treat diabetic neuropathy (nerve damage caused by diabetes). Talk to your doctor about the risks of using this medication for your condition.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking mexiletine,
- tell your doctor and pharmacist if you are allergic to mexiletine, lidocaine, any other medications, or any of the ingredients in mexiletine. Ask your pharmacist for a list of the ingredients.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: acetazolamide (Diamox); aluminum-magnesium hydroxide (Gaviscon, Maalox, Mylanta, others); amiodarone (Cordarone, Pacerone); atropine (in Lomotil, in Lonox, in Motofen); bupropion (Wellbutrin, Zyban); caffeine-containing medications (Cafergot, Esgic, Esgic Plus, Fioricet, NoDoz, Norgesic, others); chlorpheniramine (Chlor-Trimeton); cimetidine (Tagamet); clomipramine (Anafranil); diuretics ('water pills'); fluoroquinolones such as ciprofloxacin (Cipro), levofloxacin (Levaquin), moxifloxacin (Avelox), norfloxacin (Noroxin), and ofloxacin (Floxin); haloperidol (Haldol); methenamine (Hiprex, Urex); metoclopramide (Reglan); narcotic medications for pain; phenobarbital; phenytoin (Dilantin, Phenytek); potassium citrate (Urocit-K); propafenone (Rythmol); rifampin (Rifadin, Rimactane); ritonavir (Norvir, in Kaletra); certain selective serotonin reuptake inhibitors (SSRIs) such as duloxetine (Cymbalta), fluoxetine (Prozac, Sarafem), fluvoxamine, and paroxetine (Paxil); sodium bicarbonate (Soda Mint, baking soda); theophylline (Theolair, Theochron, Uniphyl); and ticlopidine (Ticlid). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with mexiletine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
- tell your doctor if you have or have ever had a heart attack, heart failure, low blood pressure, liver disease, or seizures.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking mexiletine, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking mexiletine.
- you should know that mexiletine may make you dizzy or lightheaded. Do not drive a car or operate machinery until you know how this medication affects you.
- tell your doctor if you use tobacco products. Cigarette smoking may decrease the effectiveness of this medication.
Talk to your doctor about drinking caffeine-containing beverages while taking this medicine.
Tell your doctor if you are a vegetarian or if you usually eat large amounts of citrus fruits, cranberries, vegetables, meat, or dairy products. If you do not regularly eat large amounts of these foods, continue your normal diet.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Mexiletine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- changes in appetite
- lightheadedness or dizziness
- shaking of a part of your body that you cannot control
- loss of coordination
- numbness or tingling sensation
- blurred vision
- difficulty speaking
- swelling of the hands, feet, ankles, or lower legs
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:
- irregular heartbeat
- chest pain
- extreme tiredness
- unusual bleeding or bruising
- lack of energy
- pain in the upper right part of the stomach
- yellowing of the skin or eyes
- flu-like symptoms
Mexiletine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include:
- numbness or tingling sensation
- slow, fast, or irregular heartbeat
- sudden death
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to mexiletine.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
¶This branded product is no longer on the market. Generic alternatives may be available.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Last Reviewed: September 1, 2010.