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Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Limited Use [what does this mean?]
Generic drug name: mexiletine (mex ILL et een)
Brand name(s): MEXITIL
GENERIC: not available FAMILY: Drugs for Abnormal Heart Rhythm
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

No data are available for mexiletine, as it was not tested properly in animal studies. Use during pregnancy only for clear medical reasons. Tell your doctor if you are pregnant or thinking of becoming pregnant before you take this drug.

Breast-feeding Warning

Mexiletine is excreted in human milk. Because of the potential for serious adverse effects in nursing infants, you should not take this drug while nursing.

 

Safety Warnings For This Drug [top]

FDA BLACK BOX WARNING! INCREASED RISK OF DEATH

In the National Heart, Lung, and Blood Institute’s Cardiac Arrhythmia Suppression Trial (CAST) (a long-term, multicentered, randomized, double-blind study), in patients with asymptomatic non-life-threatening ventricular (the large chambers of the heart) arrhythmias (rhythm disturbances) who had a heart attack more than six days but less than two years previous, deaths or nonfatal cardiac arrest were seen in 7.7% of those patients treated with encainide or flecainide, members of the Class 1 group of antiarrhythmic drugs, compared to 3.0% in patients receiving an inactive sugar pill or placebo.

Because of the known ability of the Class 1 drugs, such as quinidine, to cause rhythm disturbances, and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening heart rhythm disturbances, the use of the Class 1 drugs should be reserved for patients with life-threatening rhythm disturbances of the ventricles. These warnings now appear in the FDA-approved product labeling, or package insert, for all Class 1 drugs, including: disopyramide (NORPACE and generics), flecainide (TAMBOCOR), mexiletine (MEXITIL and generics), moricizine (ETHMOZINE), procainamide (PROCANBID and generics), propafenone (RYTHMOL), quinidine (DURAQUIN, QUINAGLUTE DURA-TABS, QUINIDEX, and generics), and tocainide (TONOCARD).

Facts About This Drug [top]

Mexiletine slows rapid heartbeat and stabilizes irregular heartbeats (arrhythmias). Mexiletine prevents recurrence of ventricular arrhythmias, such as premature heartbeats.

 

It is as effective as quinidine for some, but not all, arrhythmias[1] and sometimes is used with quinidine.[2] Mexiletine has little risk of organ toxicity but has a high risk of noncardiac adverse effects.[3] However, these adverse effects often cause people to stop taking mexiletine.[2],[1] Lower doses can reduce...

Mexiletine slows rapid heartbeat and stabilizes irregular heartbeats (arrhythmias). Mexiletine prevents recurrence of ventricular arrhythmias, such as premature heartbeats.

 

It is as effective as quinidine for some, but not all, arrhythmias[1] and sometimes is used with quinidine.[2] Mexiletine has little risk of organ toxicity but has a high risk of noncardiac adverse effects.[3] However, these adverse effects often cause people to stop taking mexiletine.[2],[1] Lower doses can reduce unwanted effects. People with decreased liver function should take a lower dose. At times mexiletine actually worsens some types of arrhythmias. It is not for use in minor arrhythmias. Use of mexiletine with procainamide (PROCANBID) is of little or no value.[4]

Before You Use This Drug [top]

Do not use if you have or have had:

  • cardiogenic shock
  • heart block of second or third degree without a pacemaker

Tell your doctor if you have or have had:

  • allergies to drugs
  • angina
  • congestive heart failure[5]
  • heart block or other heart problems
  • kidney[2] or liver problems
  • low blood pressure
  • myocardial infarction
  • pacemaker
  • seizures
  • pregnancy or are breast-feeding

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

When You Use This Drug [top]

  • Until you know how you react to this drug, do not drive or perform other activities requiring alertness. This drug may cause blurred vision and drowsiness.
  • You may feel dizzy when rising from a lying or sitting position. If you are lying down, hang your legs over the side of the bed for a few minutes, then get up slowly. When getting up from a chair, stay by the chair until you are sure that you are not dizzy.
  • Ask your doctor to recommend exercises suitable to your condition.
  • Quit smoking, or at least try to cut down on smoking.
  • Carry identification stating that you take mexiletine.
  • If you plan to have any surgery, including dental, tell your doctor that you take this drug.

How to Use This Drug [top]

  • If you miss a dose, take it as soon as you remember but skip it if it is less than four hours until your next scheduled dose. Do not take double doses.
  • Do not share your medication with others.
  • Take the drug at the same time(s) each day.
  • Take with food, milk, or antacids to lessen stomach upset. Space doses evenly apart. Antacids with calcium or magnesium may slow absorption of mexiletine. If you use these antacids, be consistent in usage, and avoid large doses.
  • Swallow capsule whole.
  • Store at room temperature with lid on firmly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.

Interactions with Other Drugs [top]

The following drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods are listed in Evaluations of Drug Interactions 2003 as causing “highly clinically significant” or “clinically significant” interactions when used together with any of the drugs in this section. In some sections with multiple drugs, the interaction may have been reported for one but not all drugs in this section, but we include the interaction because the drugs in this section are similar to one another. We have also included potentially serious interactions listed in the drug’s FDA-approved professional package insert or in published medical journal articles. There may be other drugs, especially those in the families of drugs listed below, that also will react with this drug to cause severe adverse effects. Make sure to tell your doctor and pharmacist the drugs you are taking and tell them if you are taking any of these interacting drugs:

cimetidine, NORVIR, PRIFTIN, rifapentine, ritonavir, SLO-BID, SLO-PHYLLIN, TAGAMET, THEO-DUR, theophylline.

Mexiletine intensifies the effect of caffeine. Eliminate or reduce your intake of beverages containing caffeine.

Adverse Effects [top]

Call your doctor immediately if you experience:

  • unusual bleeding or bruising
  • difficulty breathing
  • chest pain
  • fainting
  • fever, chills
  • unusually fast or slow heartbeat
  • seizures

Call your doctor if these symptoms continue:

  • abdominal pain
  • confusion
  • constipation
  • diarrhea
  • depression
  • dizziness, lightheadedness
  • dry mouth
  • headache
  • heartburn
  • impotence
  • nausea, vomiting, loss of appetite
  • nervousness
  • numbness or tingling of fingers, toes
  • pain in joints
  • ringing in ears
  • skin rash, yellowing of skin
  • problems sleeping
  • slurred speech
  • swelling of hands or feet
  • trembling or shaking of hands
  • unsteadiness, trouble walking
  • unusual tiredness or weakness
  • decrease in urination
  • blurred vision

Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  • blood pressure
  • blood mexiletine levels
  • electrocardiogram (ECG, EKG)
  • liver function tests

 

last reviewed June 30, 2021