Health Guide

Mexiletine (By mouth)

Mexiletine (mex-IL-e-teen)

Treats an irregular heartbeat (arrhythmia). Belongs to a class of drugs called antiarrhythmics.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have ever had an allergic reaction to mexiletine, lidocaine, or tocainide. This drug should not be used with some heart disorders, liver disease, or seizures - check with your doctor.

How to Use This Medicine:

Capsule, Long Acting Capsule

  • Your doctor will tell you how much to use and how often. Do not use more medicine or use it more often than your doctor tells you to.
  • May be taken with food, milk, or antacids to avoid stomach upset.
  • You may need to carry identification to let others know you are using mexiletine. Ask your doctor about this.

If a dose is missed:

  • If you use mexiletine 3 times daily and you miss a dose, take your medicine as soon as possible if you are less than 4 hours late. If you use the medicine twice a day, take the missed dose as soon as possible if you are less than 6 hours late.
  • Otherwise, skip the missed dose and go back to your regular dosing schedule.
  • You should not use two doses at the same time.

How to Store and Dispose of This Medicine:

  • Store at room temperature, away from heat, moisture, and direct light.
  • Keep all medicine out of the reach of children.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Tell your doctor if you are also using phenytoin (Dilantin®), or other heart medicines such as lidocaine or digoxin (Lanoxin®).
  • Do not smoke while using this medicine.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have heart disease, liver disease, seizures, or low blood pressure.
  • Tell your doctor or dentist that you are using mexiletine before having any kind of surgery.
  • Do not suddenly stop using this medicine without asking your doctor.
  • Mexiletine may make you dizzy or drowsy. Be careful if you drive a car or operate machinery.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Irregular heartbeat
  • Chest pain
  • Shortness of breath or trouble breathing
  • Skin rash, severe itching or hives

If you notice these less serious side effects, talk with your doctor:

  • Dizziness, lightheadedness, or nervousness
  • Nausea, vomiting, or upset stomach
  • Diarrhea or constipation
  • Trembling or shaking of hands
  • Blurred vision
  • Tiredness or weakness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 7/4/2018
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