Last updated on RxList: 7/7/2021
Mexitil Side Effects Center

What Is Mexitil?

Mexitil (mexiletine) 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.

What Are Side Effects of Mexitil?

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.

Dosage for Mexitil

The initial dose of Mexitil (mexiletine hcl) therapy is 200 mg every eight hours when rapid control of arrhythmia is not essential.

What Drugs, Substances, or Supplements Interact with Mexitil?

Mexitil may interact with phenytoin, mephenytoin, ethotoin, rifampin, metoclopramide, cimetidine, or theophylline. Tell your doctor all medications and supplements you use.

Mexitil During Pregnancy or Breastfeeding

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.

Additional Information

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.


In the U.S., 1 in every 4 deaths is caused by heart disease. See Answer
Mexitil Consumer Information

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Mexiletine may cause you to have abnormal liver function tests, especially if you also have congestive heart failure, or blood circulation problems.

Call your doctor at once if you have:

  • chest pain;
  • a new or a worsening irregular heartbeat pattern; or
  • liver problems--nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common side effects may include:

  • heartburn, upset stomach, nausea, vomiting;
  • dizziness, feeling lightheaded;
  • tremors, feeling nervous;
  • problems with coordination; or
  • blurred vision.

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.

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


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Mexitil Professional Information


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)


Heart Disease: Symptoms, Signs, and Causes See Slideshow

© Mexitil Patient Information is supplied by Cerner Multum, Inc. and Mexitil Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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