What is Dofetilide: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Dec 30, 2020

Dofetilide overview

BRAND NAMES:

  • Tikosyn

Generic Names:

  • Dofetilide

Uses:

  • Treats an uneven heartbeat.

Therapeutic Classes:

  • Antiarrhythmic, Group III

Forms:

  • Capsule

How it’s taken:

  • By mouth

What is Dofetilide used for?

Dofetilide comes in capsule form and is used to treat uneven heartbeats also known as arrhythmia. It works by blocking certain electrical signals in the heart that can cause an irregular heartbeat. Common side effects may include mild headache, mild dizziness or cold symptoms.

What form(s) does Dofetilide come in

  • Capsule

What are common Dofetilide doses?

  • Capsule 125MCG

  • Capsule 250MCG

  • Capsule 500MCG

Common Dofetilide prescriptions

  • Dofetilide
    125mcg capsule

  • Dofetilide
    250mcg capsule

  • Dofetilide
    500mcg capsule

How to take Dofetilide

  • Your doctor will start you on this medicine while you are in the hospital so your heart rhythm can be monitored. You will need to stay in the hospital for at least 3 days so the doctor can check your progress.

  • Once you are released from the hospital, take your medicine as directed.

  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.

  • Missed dose: If you miss a dose of this medicine, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

  • Your doctor will start you on this medicine while you are in the hospital so your heart rhythm can be monitored. You will need to stay in the hospital for at least 3 days so the doctor can check your progress.

  • Missed dose: If you miss a dose of this medicine, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

  • Once you are released from the hospital, take your medicine as directed.

What to do if you miss a dose of Dofetilide

Dofetilide contraindications

  • This medicine is not right for everyone. Do not use it if you had an allergic reaction to dofetilide, if you have long QT syndrome or severe kidney disease, or if you are on a dialysis.

Dofetilide warnings

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, heart disease, other heart rhythm problems, or mineral imbalance (such as low levels of magnesium or potassium in the blood).

  • This medicine may cause the following problems:Ventricular arrhythmiaQT prolongation

  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • Severe diarrhea, vomiting, loss of appetite, increased thirst, sweating, muscle cramps

Dofetilide interactions

  • Do not use this medicine together with cimetidine, dolutegravir, hydrochlorothiazide, hydrochlorothiazide/triamterene, ketoconazole, megestrol, prochlorperazine, trimethoprim, trimethoprim/sulfamethoxazole, or verapamil.

  • Some foods and medicines can affect how dofetilide works. Tell your doctor if you are using diltiazem, metformin, quinine, or zafirlukast.

  • Tell your doctor if you are also using certain diuretics (such as amiloride, spironolactone, triamterene), blood pressure medicines, medicine for depression, a phenothiazine medicine, medicine for infections, or medicine for HIV/AIDS.

  • Do not eat grapefruit or drink grapefruit juice while you are using this medicine.

Dofetilide side effects

Serious 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

  • Fast, slow, or pounding heartbeat

  • Fainting, dizziness, or lightheadedness

  • Chest pain or trouble breathing

  • Severe diarrhea, vomiting, loss of appetite, increased thirst, sweating, muscle cramps

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