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Dofetilide oral

Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.




WARNING: This medication may sometimes produce new, irregular heartbeats (arrhythmias). It is recommended you stay in the hospital for 3 days where proper monitoring (e.g., renal function, EKG) and support (cardiac resuscitation) is available until your body adjusts to the effects of this medication. Consult your doctor or pharmacist for more information.


This medication is used to treat irregular heartbeats (symptomatic atrial fibrillation/flutter arrhythmias). It is used to restore normal heart rhythm, and also to maintain regular, steady heartbeats.

How To Use

This medication is taken by mouth as directed. When your dosage of dofetilide is started, restarted, or increased you will be monitored in a hospital (e.g., EKG and kidney function tests, and observation). This special monitoring will minimize the chances of developing serious side effects. Your dofetilide dosage is based on your medical condition (including heart and kidney function) and response to therapy. It is very important to continue taking this medication exactly as prescribed by your doctor. Taken improperly, or without proper monitoring, this medication can build up in your bloodstream and may actually cause new, very serious irregular heartbeats. Avoid grapefruit juice while using this medication unless your doctor instructs you otherwise.

Side Effects

Nausea or headache may occur. If these effects persist or worsen, notify your doctor. Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: dizziness, fainting, irregular heartbeat. Mineral imbalances can increase the risk of developing drug side effects. Tell your doctor immediately if you have symptoms indicating a possible mineral imbalance such as: muscle cramps or weakness, prolonged diarrhea, excessive thirst or sweating, vomiting, loss of appetite. If you notice other effects not listed above, contact your doctor or pharmacist.


Tell your doctor your medical history, including: heart (e.g., prolonged QT interval) problems, kidney disease, liver disease, low blood potassium or magnesium, any allergies. Caution is advised when using this drug in the elderly, as they may have decreased kidney function. This may result in more side effects as dofetilide builds up in the bloodstream. Caution is advised when using this drug in females since they may be more sensitive to certain side effects (e.g., serious arrhythmias known as torsade de pointes). This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. It is not known whether this drug passes into breast milk. Because of the potential risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

Drug Interactions

This drug is not recommended for use with: hydrochlorothiazide. Ask your doctor or pharmacist for more details. Tell your doctor of all prescription and nonprescription medication you may use, especially of: drugs that interfere with kidney action (cation transport inhibitors, including prochlorperazine, megestrol, cimetidine, ketoconazole, and drugs containing trimethoprim), certain antipsychotics (e.g., chlorpromazine), "water pills" (diuretics such as furosemide), amiloride, triamterene, verapamil, diltiazem, metformin, azole antifungals (e.g., itraconazole), macrolide antibiotics (e.g., clarithromycin), protease inhibitors (e.g., ritonavir), quinine, zafirlukast, dronabinol, norfloxacin, antidepressants (nefazodone, and SSRI-types such as fluoxetine). Report other drugs which affect the heart rhythm (QTc prolongation), such as: pimozide, quinidine, sotalol, procainamide, sparfloxacin. Ask your doctor or pharmacist for more details. Certain other drugs for irregular heartbeats (Class I or III antiarrhythmic agents, including amiodarone) should be stopped for a period of time before starting dofetilide. Consult your doctor. If your doctor stops your dofetilide treatment in order to more safely prescribe an interacting drug, wait 2 days before starting the new drug, unless instructed otherwise. This allows the dofetilide to be removed from your bloodstream. Consult your doctor or pharmacist for more details. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include fast or irregular heartbeat, fainting, and loss of consciousness.


Do not share this medication with others. Laboratory and/or medical tests (e.g., EKG, kidney function, potassium and magnesium blood tests) will be performed to monitor your progress.

Missed Dose

If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.


Store at room temperature between 59 and 86 degrees F (15 to 30 degrees C) away from light and moisture.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).