Mexiletine

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Mexiletine. If you are concerned about side effects, discuss the risks and benefits of Mexiletine with your doctor.

The following side effects have been reported by at least 1% of people taking Mexiletine. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• appetite changes
• changed sleep habits
• Constipation
• Diarrhea
• Dry Mouth
• fatigue
• headache
• heartburn
• lightheadedness
• nausea
• nervousness
• rash
• unusual prickling or burning sensations
• weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• abdominal pain
• changes in thoughts or behaviour
• chest pain
• confusion
• coordination problems
• new abnormal heart rhythms (fast, pounding heartbeat)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• symptoms of Depression (e.g., loss of interest in activities, appetite changes, sleep changes, feeling hopeless)
• symptoms of heart failure (e.g., shortness of breath, swelling of the hands and feet)
• trembling
• vision changes

Stop taking the medication and seek immediate medical attention if any of the following occur:

• seizures
• signs of a Anaphylaxis (severe allergic reaction) (e.g., Hives, peeling or blistering skin, difficulty breathing, swelling of the mouth or throat)
• signs of a severe skin reaction (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with Fever or discomfort)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Mexiletine.

100 mg
Each hard gelatin capsule with opaque scarlet cap and opaque orange body, with "N" and "100" imprinted on opposing cap and body portions of the capsule, contains 100 mg of mexiletine HCl. Nonmedicinal ingredients: colloidal silicon dioxide, D&C Red No. 33, FD&C Blue No. 1, FD&C Red No. 3, FD&C Red No. 40, gelatin, magnesium stearate, parabens, pregelatinized starch, silicon dioxide, sodium lauryl sulfate, talc, titanium dioxide, and Yellow No. 6. Gluten- and tartrazine-free.

200 mg
Each scarlet hard gelatin capsule, with "N" and "200" imprinted on opposing cap and body portions of the capsule, contains 200 mg of mexiletine HCl. Nonmedicinal ingredients: colloidal silicon dioxide, D&C Red No. 33, FD&C Blue No. 1, FD&C Red No. 40, gelatin, magnesium stearate, parabens, pregelatinized starch, silicon dioxide, sodium lauryl sulfate, talc, and titanium dioxide. Gluten- and tartrazine-free.

Do not use Mexiletine if you:

• are allergic to mexiletine or any ingredients of the medication
• are allergic to amide anaesthetics
• have cardiogenic shock
• have second- or third-degree heart block (without a pacemaker)

There may be an interaction between mexiletine and any of the following:

• Bupropion
• Bromazepam
• caffeine
• cannabis
• Clozapine
• Cobicistat
• Duloxetine
• etravirine
• Lacosamide
• Leflunomide
• melatonin
• Metoclopramide
• Olanzapine
• other medications used to treat abnormal heart rhythms (e.g., Amiodarone, lidocaine, quinidine, procainamide, Propafenone, Disopyramide)
• Pentoxifylline
• Phenytoin
• Propranolol
• quinine
• Rasagiline
• Ropinirole
• selective serotonin reuptake inhibitors (SSRIs; e.g., Fluvoxamine, Fluoxetine, Paroxetine, Citalopram, Escitalopram)
• Teriflunomide
• theophyllines (e.g., Aminophylline, Oxtriphylline, Theophylline)
• Tizanidine
• tobacco (smoked)
• tricyclic antidepressants (e.g., Clomipramine, Desipramine, Imipramine)

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Mexiletine. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Mexiletine.

Abnormal heart rhythms: Certain medications used to treat abnormal heart rhythms, including mexiletine, may cause new abnormal heart rhythms or worsen existing ones. Your doctor will monitor you closely while you are taking mexiletine. If you experience a fast, slow, or irregular heartbeat; fainting; heart palpitations; or dizziness while taking Mexiletine, contact your doctor immediately.

Blood clotting: Mexiletine can reduce the number of platelet cells in the blood. Platelets help the blood to clot, and a shortage could make you bleed more easily. Tell your doctor about any signs that your blood is not clotting as quickly as usual. Such symptoms may include black and tarry stools, blood in the urine, easy bruising, or cuts that won't stop bleeding.

Dizziness, tremor, and coordination: Mexiletine may cause dizziness, tremor, or changes in coordination. Do not drive or operate machinery until you know how Mexiletine affects you.

Drug Reactions with Eosinophilia and Systemic Symptoms (DRESS): DRESS is a type of allergic reaction that can affect multiple organs. Early symptoms often include fever, rash on the face or upper body, and swelling of the face. In severe cases, organs such as the kidney or liver can become inflamed and function decreases. If you experience unusual symptoms, contact your doctor as soon as possible.

Heart failure: Mexiletine can cause or worsen heart failure. If you have heart failure and are taking Mexiletine, your doctor will monitor you closely during treatment. If you notice shortness of breath; weight gain; or swelling in the hands, feet, or lower legs while taking mexiletine, contact your doctor immediately.

Infection: Mexiletine can reduce the number of cells that fight infection in the body (white blood cells). If possible, avoid contact with people who have contagious infections. Tell your doctor immediately if you begin to notice the signs of an infection such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.

Liver problems: Liver disease or reduced liver function may cause Mexiletine to build up in the body, causing side effects. Mexiletine can cause liver problems. Your doctor will monitor your liver function while you are taking Mexiletine. If you experience nausea, abdominal pain, yellowing of the skin or eyes, pale stools, or dark urine while taking mexiletine, contact your doctor immediately. People with liver problems should discuss with their doctor how Mexiletine may affect their medical condition, how their medical condition may affect the dosing and effectiveness of Mexiletine, and whether any special monitoring is needed.

Low Blood Pressure: Mexiletine may cause or worsen low blood pressure. Tell your doctor if you experience symptoms of severely decreased blood pressure, such as weakness or dizziness, particularly when rising suddenly from a sitting or lying position. If you have low blood pressure, discuss with your doctor how Mexiletine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Mexiletine, and whether any special monitoring is needed.

Seizures: People with a history of seizures should discuss with their doctor how Mexiletine may affect their medical condition, how their medical condition may affect the dosing and effectiveness of Mexiletine, and whether any special monitoring is needed.

Pregnancy: Mexiletine should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Mexiletine, contact your doctor immediately.

Breast-feeding: Mexiletine passes into breast milk. If you are a breast-feeding mother and are taking mexiletine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using Mexiletine have not been established for children.

Mexiletine belongs to the class of medications called antiarrhythmics. It is used to treat certain types of abnormal heart rhythms. It works by affecting nerve signals in the cells of the heart, which helps the heart beat more regularly.

Mexiletine may be available under multiple brand names and/or in several different forms. Any specific brand name of Mexiletine may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of Mexiletine may not be used for all of the conditions discussed here.

Your doctor may have suggested Mexiletine for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking Mexiletine, speak to your doctor. Do not stop taking Mexiletine without consulting your doctor.

Do not give Mexiletine to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take Mexiletine if their doctor has not prescribed it.