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.
Why is this medicine prescribed?
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.
Are there other uses for this medicine?
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.
How should this medicine be used?
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.
What special precautions should I follow?
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.
- 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.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking mexiletine.
- tell your doctor if you use tobacco products. Cigarette smoking may decrease the effectiveness of this medication.
What special dietary instructions should I follow?
Talk to your doctor about drinking caffeine-containing beverages while taking this medicine.
What should I do if I forget to take a dose?
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.
What should I do in case of overdose?
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help . If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
Symptoms of overdose may include:
- numbness or tingling sensation
- slow, fast, or irregular heartbeat
- sudden death
What side effects can this medicine cause?
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.
What should I know about storage and disposal of 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).
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website ( http://goo.gl/c4Rm4p ) for more information if you do not have access to a take-back program.
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org
What other information should I know?
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.