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Discontinued Warning IconPlease Note: This Brand Name drug is no longer available in the US.
(Generic versions may still be available.)

Mexitil Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 10/6/2015

Mexitil Capsules (mexiletine hydrochloride) is an antiarrhythmic drug prescribed for the treatment of certain types of ventricular arrhythmias. The brand name drug Mexitil is no longer available in the U.S. Generic versions may be available. Common side effects of Mexitil (mexiletine hydrochloride) include nausea, vomiting, upset stomach, heartburn, decreased appetite, headache, blurred vision, rash, dizziness, lightheadedness, tiredness, poor coordination, dry mouth, diarrhea, constipation, weakness, numbness, tingling, tremor (shaking), ringing in your ears, or depression.

The initial dose of Mexitil (mexiletine hcl) therapy is 200 mg every eight hours when rapid control of arrhythmia is not essential. Mexitil may interact with phenytoin, mephenytoin, ethotoin, rifampin, metoclopramide, cimetidine, or theophylline. Tell your doctor all medications and supplements you use. There are no adequate and well-controlled studies in pregnant women; this drug should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. If the use of Mexitil is deemed essential an alternative to breastfeeding should be considered. Mexitetine hydrochloride has not been studied in the pediatric population.

Our Mexitil (mexiletine hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is Patient Information in Detail?

Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.

Mexitil in Detail - Patient Information: Side Effects

If you experience any of the following serious side effects, stop taking mexiletine and seek emergency medical attention:

  • an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
  • a new or a worsening irregular heartbeat pattern;
  • wheezing, coughing, chest pain, or chest discomfort;
  • unusual bruising or bleeding; or
  • fever, sore throat, a sore mouth, mouth ulcers, or an infection.

Other, less serious side effects may be more likely to occur. Continue to take mexiletine and talk to your doctor if you experience

  • dizziness, lightheadedness, or tiredness;
  • poor coordination;
  • dry mouth;
  • upset stomach, heartburn, vomiting, or decreased appetite;
  • diarrhea or constipation;
  • headache or blurred vision;
  • weakness;
  • numbness, tingling, or tremor (shaking);
  • ringing in your ears;
  • a rash; or
  • depression.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Mexitil (Mexiletine HCl)

What is Patient Information Overview?

A concise overview of the drug for the patient or caregiver from First DataBank.

Mexitil Overview - Patient Information: Side Effects

SIDE EFFECTS: See also Warning section.

Nausea, vomiting, heartburn, dizziness, lightheadedness, vision problems (such as blurred vision), headache, shaking, nervousness, or problems with muscle control (coordination difficulties) may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these rare but serious side effects occur: worsening symptoms of heart failure (such as ankle/leg swelling, increased tiredness, increased shortness of breath when lying down), signs of liver problems (such as persistent nausea/vomiting, stomach/abdominal pain, yellowing eyes/skin, dark urine).

Seek immediate medical attention if any of these rare but very serious side effects occur: chest pain, seizure.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

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

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the entire patient information overview for Mexitil (Mexiletine HCl)

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Mexitil FDA Prescribing Information: Side Effects
(Adverse Reactions)


MEXITIL (mexiletine hydrochloride, USP) commonly produces reversible gastrointestinal and nervous system adverse reactions but is otherwise well tolerated. MEXITIL (mexiletine hcl) has been evaluated in 483 patients in one-month and three-month controlled studies and in over 10,000 patients in a large compassionate use program. Dosages in the controlled studies ranged from 600-1200 mg/day; some patients (8%) in the compassionate use program were treated with higher daily doses (1600-3200 mg/day). In the three-month controlled trials comparing MEXITIL (mexiletine hcl) to quinidine, procainamide and disopyramide, the most frequent adverse reactions were upper gastrointestinal distress (41%), lightheadedness (10.5%), tremor (12.6%) and coordination difficulties (10.2%). Similar frequency and incidence were observed in the one-month placebo-controlled trial. Although these reactions were generally not serious, and were dose-related and reversible with a reduction in dosage, by taking the drug with food or antacid or by therapy discontinuation, they led to therapy discontinuation in 40% of patients in the controlled trials. Table 1 presents the adverse events reported in the one-month placebo-controlled trial.

Table 1 : Comparative Incidence (%) of Adverse Events Among Patients Treated with Mexiletine and Placebo in the 4- Week, Double-blind Crossover Trial

  Palpitations 7.5 10.2
  Chest Pain 7.5 4.1
  Increased Ventricular Arrhythmia /PVC's 1.9 -
  Nausea/Vomiting/Heartburn 39.6 6.1
Central Nervous System
  Dizziness/ 26.4 14.3
  Tremor 13.2 -
  Nervousness 11.3 6.1
  Coordination Difficulties 9.4 -
  Changes in Sleep Habits 7.5 16.3
  Paresthesias/Numbness 3.8 2.0
  Weakness 1.9 4.1
  Fatigue 1.9 2.0
  Tinnitus 1.9 4.1
  Confusion/Clouded Sensorium 1.9 2.0
  Headache 7.5 6.1
  Blurred Vision/Visual Disturbances 7.5 2.0
  Dyspnea/Respiratory 5.7 10.2
  Rash 3.8 2.0
  Non-specific Edema 3.8 -

Table 2 presents the adverse reactions occurring in one percent or more of patients in the three-month controlled studies.

Table 2: Comparative Incidence (%) of Adverse Events Among Patients Treated with Mexiletine or Control Drugs in the 12-Week Double-blind Trials

N = 430
N = 262
N = 78
  Palpitations 4.3 4.6 1.3
  Chest Pain 2.6 3.4 1.3
  Angina/Angina-like Pain 1.7 1.9 2.6
  Increased Ventricular Arrhythmias/PVC's 1.0 2.7 2.6
  Nausea/Vomiting/Heartburn 39.3 21.4 33.3
  Diarrhea 5.2 33.2 2.6
  Constipation 4.0 - 6.4
  Changes in Appetite 2.6 1.9 -
  Abdominal Pain/Cramps/Discomfort 1.2 1.5 -
Central Nervous System
  Dizziness/Lightheadedness 18.9 14.1 14.1
  Tremor 13.2 2.3 3.8
  Coordination Difficulties 9.7 1.1 1.3
  Changes in Sleep Habits 7.1 2.7 11.5
  Weakness 5.0 5.3 7.7
  Nervousness 5.0 1.9 6.4
  Fatigue 3.8 5.7 5.1
  Speech Difficulties 2.6 0.4 -
  Confusion/Clouded Sensorium 2.6 - 3.8
  Paresthesias/Numbness 2.4 2.3 2.6
  Tinnitus 2.4 1.5 -
  Depression 2.4 1.1 1.3
  Blurred Vision/Visual Disturbances 5.7 3.1 5.1
  Headache 5.7 6.9 7.7
  Rash 4.2 3.8 10.3
  Dyspnea/ Respiratory 3.3 3.1 5.1
  Dry Mouth 2.8 1.9 5.1
  Arthralgia 1.7 2.3 5.1
  Fever 1.2 3.1 2.6

Less than 1%: Syncope, edema, hot flashes, hypertension, short-term memory loss, loss of consciousness, other psychological changes, diaphoresis, urinary hesitancy/retention, malaise, impotence/decreased libido, pharyngitis, congestive heart failure.

An additional group of over 10,000 patients has been treated in a program allowing administration of MEXITIL (mexiletine hydrochloride, USP) under compassionate use circumstances. These patients were seriously ill with the large majority on multiple drug therapy. Twenty-four percent of the patients continued in the program for one year or longer. Adverse reactions leading to therapy discontinuation occurred in 15 percent of patients (usually upper gastrointestinal system or nervous system effects). In general, the more common adverse reactions were similar to those in the controlled trials. Less common adverse events possibly related to MEXITIL (mexiletine hcl) use include:

Cardiovascular System: Syncope and hypotension, each about 6 in 1000; bradycardia, about 4 in 1000; angina/angina-like pain, about 3 in 1000; edema, atrioventricular block/conduction disturbances and hot flashes, each about 2 in 1000; atrial arrhythmias, hypertension and cardiogenic shock, each about 1 in 1000.

Central Nervous System: Short-term memory loss, about 9 in 1000 patients; hallucinations and other psychological changes, each about 3 in 1000; psychosis and convulsions/seizures, each about 2 in 1000; loss of consciousness, about 6 in 10,000.

Digestive: Dysphagia, about 2 in 1000; peptic ulcer, about 8 in 10,000; upper gastrointestinal bleeding, about 7 in 10,000; esophageal ulceration, about 1 in 10,000. Rare cases of severe hepatitis/acute hepatic necrosis.

Skin: Rare cases of exfoliative dermatitis and Stevens-Johnson Syndrome with MEXITIL (mexiletine hydrochloride, USP) treatment have been reported.

Laboratory:Abnormal liver function tests, about 5 in 1000 patients; positive ANA and thrombocytopenia, each about 2 in 1000; leukopenia (including neutropenia and agranulocytosis), about 1 in 1000; myelofibrosis, about 2 in 10,000 patients.

Other: Diaphoresis, about 6 in 1000; altered taste, about 5 in 1000; salivary changes, hair loss and impotence/decreased libido, each about 4 in 1000; malaise, about 3 in 1000; urinary hesitancy/retention, each about 2 in 1000; hiccups, dry skin, laryngeal and pharyngeal changes and changes in oral mucous membranes, each about 1 in 1000; SLE syndrome, about 4 in 10,000.


Blood dyscrasias were not seen in the controlled trials but did occur among 10,867 patients treated with mexiletine in the compassionate use program (see PRECAUTIONS).

Myelofibrosis was reported in two patients in the compassionate use program: one was receiving long-term thiotepa therapy and the other had pretreatment myeloid abnormalities.

In post-marketing experience, there have been isolated, spontaneous reports of pulmonary changes including pulmonary infiltration and pulmonary fibrosis during MEXITIL (mexiletine hcl) therapy with or without other drugs or diseases that are known to produce pulmonary toxicity. A causal relationship to MEXITIL (mexiletine hcl) therapy has not been established. In addition, there have been isolated reports of drowsiness, nystagmus, ataxia, dyspepsia, hypersensitivity reaction, and exacerbation of congestive heart failure in patients with pre-existing compromised ventricular function. There have been rare reports of pancreatitis associated with MEXITIL (mexiletine hcl) treatment.

Read the entire FDA prescribing information for Mexitil (Mexiletine HCl)

Mexitil - User Reviews

Mexitil User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Mexitil sorted by most helpful. Patient Discussions FAQs

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