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Uses

What is dofetilide used for?

Dofetilide is commonly used to treat the following conditions.

  •  Atrial fibrillation, which is a condition that results when the top part of your heart (called the atria) and the bottom part of the heart (called the ventricles) are not working together, which can lead to your heart not beating in rhythm
  • Atrial flutter, which is a condition in which electrical impulses from your heart do not follow their normal pathway, causing your heart to beat too fast

Dofetilide may also be used for other conditions as determined by your healthcare provider.

How does dofetilide work (mechanism of action)?

Dofetilide is medicine used to control your heart rate or rhythm (antiarrhythmic). Dofetilide works by blocking certain electrical signals in the heart that can cause an irregular heartbeat. This helps keep your heart rhythm normal.

How is dofetilide supplied (dosage forms)?

Dofetilide is available in the following dosage forms that are taken by mouth.

  • 125 mcg oral capsules
  • 250 mcg oral capsules
  • 500 mcg oral capsules

How should I store dofetilide?

Dofetilide should be stored between 59° to 86°F (15° to 30°C). Dofetilide should be stored in a tightly closed container. Dofetilide should be kept in a location that is out of reach of children and away from moisture and humidity.

Side Effects

What are the most common side effects of dofetilide?

The most common side effects of dofetilide are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Headache
  • Chest pain
  • Dizziness

There may be other side effects of dofetilide that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of dofetilide?

While less common, the most serious side effects of dofetilide are described below, along with what to do if they happen.

Severe Allergic Reactions. Dofetilide may cause allergic reactions, which can be serious. Stop taking dofetilide and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Heart Rhythm Changes. Dofetilide may cause heart rhythm problems, including Torsade de Pointes, which can be fatal. Some people have a higher risk of this, including people with existing heart disease or who take other medicines that affect the heart. Get emergency help if you have any of the following signs of heart rhythm changes.

  • Chest pain
  • Shortness of breath
  • Feeling dizzy, lightheaded, or fainting
  • Changes in your heart rate or rhythm, such as a fast, slow, pounding or skipping heartbeat

Electrolyte Changes. Dofetilide may cause changes to the levels of certain minerals in your body, called electrolytes. For example, it may cause low potassium levels (hypokalemia), low sodium levels (hyponatremia), or low chloride levels (hypochloremia). These changes can be serious. Keep appointments for blood work, so that your healthcare provider can check your electrolyte levels, especially if you take certain other medicines. Call your healthcare provider if you have any of the following symptoms of electrolyte changes.

  • Unusual sweating
  • Increased thirst
  • Weakness
  • Unusual tiredness
  • Muscle cramps or twitching
  • Constipation
  • Nausea, vomiting, or loss of appetite
  • Severe diarrhea
  • Dizziness
  • Restlessness or irritability
  • Difficulty breathing
  • Confusion or decreased alertness

Warnings & Precautions

Who should not use dofetilide?

Allergies to Ingredients. People who are allergic to any of the following should not take dofetilide.

  • Dofetilide
  • Tikosyn
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific dofetilide products they stock.

Long QT Syndrome. Dofetilide should not be used if you have an irregular heartbeat called long QT syndrome.

Kidney Problems or On Kidney Dialysis. Dofetilide should not be used if your kidneys are not working as well as they should be. If there is a concern about the health of your kidneys, your healthcare provider may do tests to determine if they are working well enough to take this medicine.

Drug Interactions. Dofetilide should not be taken while you are using certain other medicines. Before taking dofetilide, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

What should I know about dofetilide before using it?

Do not take dofetilide unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share dofetilide with other people, even if they have the same condition as you. It may harm them.

Keep dofetilide out of the reach of children.

What should I tell my healthcare provider before using dofetilide?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if dofetilide is right for you.

In particular, before taking dofetilide, tell your healthcare provider if you have the following problems.

  • Heart problems
  • Kidney problems
  • Liver problems

Additionally, tell your doctor if you take medicines to treat the following.

  • Heart problems
  • High blood pressure
  • Depression or other mental problems
  • Asthma
  • Allergies, or hay fever
  • Skin problems
  • Infections

Pregnancy. It is not known if or how dofetilide could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.

Breastfeeding. Do not breastfeed while taking dofetilide. It is not known if dofetilide passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does dofetilide interact with foods or drinks?

There are no known interactions between dofetilide and foods or drinks.

There are no known interactions between dofetilide and alcohol. If you choose to drink alcohol while taking this medicine, it is advisable that you only drink alcohol in moderation because drinking alcohol will increase the chance of heart and liver problems. The risk of dizziness may be increased if you drink alcohol while taking dofetilide.

Does dofetilide interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking dofetilide.

  • Cimetidine (Tagamet HB), which is a medicine used for heartburn
  • Verapamil (Verelan, Verelan PM), which is a medicine used for high blood pressure or chest pain
  • Ketoconazole, which is a medicine used for fungal infections
  • Trimethoprim alone (Primsol, Proloprim, Trimpex) or the combination of trimethoprim and sulfamethoxazole (Bactrim), which is a medicine used for bacterial infections
  • Prochlorperazine (Compro), which is a medicine used to treat nausea and vomiting, anxiety, and schizophrenia
  • Megestrol, which is a synthetic hormone medicine
  • Dolutegravir (Tivicay), which is a medicine used for HIV
  • Hydrochlorothiazide, which is a medicine used to reduce edema (fluid retention) and blood pressure

This may not be a complete list of medicines that can interact with dofetilide. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much dofetilide?

If you or someone else has used too much dofetilide, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of dofetilide?

If you miss a dose of dofetilide, just take the next dose at your scheduled time. Do not take two doses of dofetilide at the same time.