Mexiletine, Oral

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KEY POINTS

• This medicine is taken by mouth to correct an irregular heartbeat. Take it exactly as directed.
• Keep all appointments for tests to see how this medicine affects you.
• This medicine may cause liver damage or other unwanted side effects. Tell your healthcare provider if you have any side effects that are serious, continue, or get worse.
• Tell all healthcare providers who treat you about all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take.

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What are other names for this medicine?

Type of medicine: antiarrhythmic (treats irregular heartbeat)

Generic and brand names: mexiletine, oral

What is this medicine used for?

This medicine is taken by mouth to treat abnormal heart rhythms. Because this medicine may cause severe or deadly side effects, it is only used in people with irregular heart rhythms that may be life-threatening.

This medicine may be used to treat other conditions as determined by your healthcare provider.

What should my healthcare provider know before I take this medicine?

Before taking this medicine, tell your healthcare provider if you have ever had:

• An allergic reaction to any medicine
• Heart failure
• Heart disease, slow heart rate, or a pacemaker
• Low levels of potassium or magnesium in the blood
• Low blood pressure
• Kidney or liver disease
• Seizures

Females of childbearing age: Tell your healthcare provider if you are pregnant or plan to become pregnant. It is not known whether this medicine will harm an unborn baby. Do not breast-feed while taking this medicine without your healthcare provider's approval.

How do I take it?

This medicine is first given while you are in the hospital where you will be watched closely.

Check the label on the medicine for directions about your specific dose. Take this medicine exactly as directed by your healthcare provider. Do not take more or less of it or take it longer than prescribed. Do not stop taking this medicine without your healthcare provider's approval. Check with your healthcare provider before using this medicine in children under age 18.

Take this medicine with food.

What if I miss a dose?

This medicine works best when there is a constant amount in your body. Take the medicine at the same time every day in evenly spaced doses. If you miss a dose, take it as soon as you remember unless it is almost time for the next scheduled dose. In that case, skip the missed dose and take the next one as directed. Do not take double doses. If you are not sure of what to do if you miss a dose, or if you miss more than one dose, contact your healthcare provider.

What if I overdose?

If you or anyone else has intentionally taken too much of this medicine, call 911 or go to the emergency room right away. If you pass out, have seizures, weakness or confusion, or have trouble breathing, call 911. If you think that you or anyone else may have taken too much of this medicine, call the poison control center. Do this even if there are no signs of discomfort or poisoning. The poison control center number is 800-222-1222.

Symptoms of an acute overdose may include: nausea, seizures, numbness, tingling, drowsiness, confusion, tiredness, dizziness, lightheadedness, fainting, slow or irregular heartbeat, coma.

What should I watch out for?

You need regular checks of your heart rhythm and blood tests while taking this medicine to see how this medicine affects you. Keep all appointments.

This medicine can cause liver problems. Contact your healthcare provider right away if you develop severe tiredness, nausea, vomiting, loss of appetite, dark urine, fever, headache, muscle or joint pain, yellowing of your eyes and skin. These are signs of possible liver damage.

This medicine may make you feel dizzy or lightheaded. Do not drive or operate machinery unless you are fully alert.

If you develop hives, an itchy rash, or peeling skin, stop taking the medicine and contact your provider right away.

If you need emergency care, surgery, lab tests, or dental work, tell the healthcare provider or dentist you are taking this medicine.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your healthcare provider if you have any side effects that continue or get worse.

Life-threatening (Report these to your healthcare provider right away. If you cannot reach your healthcare provider right away, get emergency medical care or call 911 for help.): Allergic reaction (hives; itching; rash; trouble breathing; chest pain or tightness in your chest; swelling of your lips, tongue, and throat).

Serious (Report these to your healthcare provider right away.): Chest pain, increased swelling in legs and feet or sudden weight gain, worsening of irregular heartbeat, pounding in the chest, unusual tiredness or weakness, trouble breathing, unusual bruising or bleeding, chills, cough, fever, sore throat, mouth sores, yellowing of the eyes and skin; dark urine, light-colored bowel movements, severe or continued vomiting or diarrhea, seizures.

Other: Blurred vision, confusion, nervousness, headache, constipation, diarrhea, heartburn, dizziness, drowsiness, lightheadedness, loss of appetite, nausea, vomiting, numbness or tingling in hands or feet, ringing in ears, dizziness, stomach pain, tremor, trouble sleeping, dry mouth.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these products together might cause harmful side effects. Talk to your healthcare provider if you are taking:

• Alosetron (Lotronex)
• Anagrelide (Agrylin)
• Antiarrhythmic medicines (to treat irregular heartbeat) such as amiodarone (Cordarone, Pacerone), disopyramide (Norpace), dofetilide (Tikosyn), dronedarone (Multaq), lidocaine (Lidoderm, Xylocaine), procainamide, propafenone (Rythmol), and quinidine
• Antibiotics such as azithromycin (Zithromax, Zmax), bedaquiline (Sirturo), ciprofloxacin (Cipro), clarithromycin (Biaxin), erythromycin (E.E.S., Ery-Tab, Erythrocin), isoniazid, levofloxacin (Levaquin), moxifloxacin (Avelox), pentamidine (NebuPent, Pentam), rifampin (Rifadin), and telithromycin (Ketek)
• Antidepressants such as citalopram (Celexa), clomipramine, desipramine (Norpramin), duloxetine (Cymbalta), escitalopram (Lexapro), fluoxetine (Prozac), fluvoxamine (Luvox), imipramine (Tofranil), mirtazapine (Remeron), sertraline (Zoloft), trazodone, and venlafaxine (Effexor)
• Antifungal medicines such as ketoconazole (Nizoral) and terbinafine (Lamisil)
• Antipsychotic medicines such as aripiprazole (Abilify), asenapine (Saphris), chlorpromazine, clozapine (Clozaril, FazaClo), droperidol (Inapsine), haloperidol (Haldol), iloperidone (Fanapt), olanzapine (Zyprexa), paliperidone (Invega), pimozide (Orap), prochlorperazine (Compro), quetiapine (Seroquel), risperidone (Risperdal), thioridazine, thiothixene (Navane), trifluoperazine, and ziprasidone (Geodon)
• Antiseizure medicines such as carbamazepine (Carbatrol, Epitol, Equetro, Tegretol), fosphenytoin (Cerebyx), phenytoin (Dilantin, Phenytek), and primidone (Mysoline)
• Barbiturates such as pentobarbital (Nembutal), phenobarbital, and secobarbital (Seconal)
• Bupropion (Aplenzin, Forfivo, Wellbutrin, Buproban, Zyban)
• Caffeine
• Cancer medicines such as abiraterone (Zytiga), arsenic trioxide (Trisenox), bendamustine (Treanda), dacarbazine, flutamide, imatinib (Gleevec), nilotinib (Tasigna), and vemurafenib (Zelboraf)
• Cimetidine (Tagamet)
• Cinacalcet (Sensipar)
• Donepezil (Aricept)
• Gemfibrozil (Lopid)
• HIV medicines such as darunavir (Prezista), delavirdine (Rescriptor), elvitegravir/cobicistat/emtricitabine/tenofovir (Stribild), etravirine (Intelence), lopinavir/ritonavir (Kaletra), ritonavir (Norvir), saquinavir (Invirase), and tipranavir (Aptivus)
• Methoxsalen (8-MOP, Oxsoralen Ultra, Uvadex)
• Metoclopramide (Metozolv, Reglan)
• Muscle relaxants such as cyclobenzaprine (Amrix) and tizanidine (Zanaflex)
• Narcotic pain medicines such as codeine, hydrocodone/acetaminophen (Norco, Vicodin), morphine (Kadian, MS Contin), oxycodone (OxyContin, Roxicodone), and oxycodone/acetaminophen (Percocet, Roxicet)
• Nicardipine (Cardene)
• Parkinson’s disease medicines such as rasagiline (Azilect) and ropinirole (Requip)
• Paroxetine (Brisdelle, Paxil, Pexeva)
• Pirfenidone (Esbriet)
• Pomalidomide (Pomalyst)
• Primaquine
• Ramelteon (Rozerem)
• Sodium bicarbonate (Alka-Seltzer)
• Theophylline
• Vitamin C (ascorbic acid) or products that contain vitamin C

Many more medicines may interact with this medicine. Be sure that you tell your healthcare provider about all other medicines you are taking, especially those prescribed by other healthcare providers.

If you are not sure if your medicines might interact, ask your pharmacist or healthcare provider. Keep a list of all your medicines with you. List all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take. Be sure that you tell all healthcare providers who treat you about all the products you are taking.

How should I store this medicine?

Store this medicine at room temperature. Keep the container tightly closed. Protect it from heat, high humidity, and bright light.

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This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your healthcare provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.