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Dofetilide (By mouth)

Dofetilide (doe-FET-i-lide)

Treats an irregular heartbeat (arrhythmia). Belongs to a class of drugs called antiarrhythmics.

Brand Name(s):


There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to dofetilide. Do not use this medicine if you are also using cimetidine (Tagamet®), trimethoprim (Proloprim®), trimethoprim with sulfamethoxazole (Bactrim®, Septra®), ketoconazole (Nizoral®), verapamil (Calan®), prochlorperazine (Compazine®), megestrol (Megace®), or hydrochlorothiazide (alone or in combination with triamterene), such as Dyazide® or Maxzide®. You should not use this medicine if you have a heart condition called "long QT syndrome," or severe kidney disease.

How to Use This Medicine:


  • Your doctor will start you on this medicine in the hospital in order to check your heart rhythm and find the right dose for you. You will need to stay in the hospital a minimum of 3 days so the doctor can monitor your progress.
  • Take your medicine as directed.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are also using amiloride (Midamor®), bepridil (Vascor®), metformin (Glucophage®), triamterene (Dyrenium®), medicine for depression (such as amitriptyline, fluoxetine, nefazodone, nortriptyline, Elavil®, Pamelor®, Prozac®, Sarafem®, or Vivactil®), medicine for infections (such as erythromycin, levofloxacin, moxifloxacin, sparfloxacin, Avelox®, Levaquin®, or Zagam®). Tell your doctor if you also use medicine for HIV or AIDS (such as indinavir, ritonavir, saquinavir, Crixivan®, Fortovase®, or Norvir®), medicine for mental disorders (such as haloperidol, mesoridazine, pimozide, quetiapine, thioridazine, ziprasidone, Geodon®, Haldol®, Mellaril®, Orap®, Serentil®, or Seroquel®), or other medicines for heart rhythm problems (such as amiodarone, disopyramide, procainamide, Cordarone®, Norpace®, or Procanbid®).
  • Do not eat grapefruit or drink grapefruit juice while you are using this medicine.
  • Ask your doctor before you take any new medicine or supplement, including any nonprescription (over-the-counter) medicines.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding. Tell your doctor if you have any heart problems, kidney disease, or mineral imbalance (such as low potassium in the blood).
  • Make sure anyone who treats you knows that you are using this medicine. If you go to the hospital or to a new doctor, give them a list of all the medicines and supplements that you are using.
  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Chest pain.
  • Severe diarrhea.
  • Sweating more than usual.
  • Unusually fast or uneven heartbeat.
  • Vomiting, loss of appetite, or thirst.

If you notice these less serious side effects, talk with your doctor:

  • Cough, runny nose, or sore throat.
  • Dizziness.
  • Headache.
  • Nausea.

If you notice other side effects that you think are caused by this medicine, tell your doctor

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

Last Updated: 4/4/2014

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