Dofetilide can cause your heart to beat irregularly. You will need to be in a hospital or another place where you can be monitored closely by your doctor for at least 3 days when you are started or restarted on dofetilide. It is important to read the patient information provided to you every time you begin therapy with dofetilide.
Dofetilide is used to treat irregular heartbeats. It improves your heart rhythm by relaxing an overactive heart.
This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
Dofetilide comes as a capsule to take by mouth. It is usually taken twice a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take dofetilide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor. Do not take a double dose.
Dofetilide controls abnormal heart rhythms but does not cure them. Continue to take dofetilide even if you feel well. Do not stop taking dofetilide without talking to your doctor.
Before taking dofetilide,
- tell your doctor and pharmacist if you are allergic to dofetilide or any other drugs.
- tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially antipsychotics, bepridil (Vascor), cimetidine (Tagamet), cisapride (Propulsid), clarithromycin (Biaxin), diltiazem (Cardizem), diuretics ('water pills'), erythromycin (E.E.S., E-Mycin, others), HIV protease inhibitors such as ritonavir (Norvir), itraconazole (Sporanox), ketoconazole (Nizoral), medications for dizziness or nausea, medications for depression such as amitriptyline (Elavil) or fluoxetine (Prozac), megestrol (Megace), metformin (Glucophage), other medications for irregular heart beats such as amiodarone (Cordarone), norfloxacin (Noroxin), prochlorperazine (Compazine), quinine (Formula Q), trimethoprim (Proloprim, Trimpex), trimethoprim and sulfamethoxazole (Bactrim, Septra), verapamil (Calan, Covera, Verelan), zafirlukast (Accolate), and vitamins.
- tell your doctor if you have or have ever had long QT syndrome (a type of heart problem), or kidney or liver disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking dofetilide, call your doctor.
Talk to your doctor before drinking grapefruit juice. It may be best to drink other fruit juices while taking dofetilide.
Skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Dofetilide may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- chest pain
- respiratory infection
- flu-like symptoms
- stomach pain
- back pain
- difficulty sleeping
If you experience any of the following symptoms, call your doctor immediately:
- irregular heartbeat
- upset stomach
- loss of appetite or thirst
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Keep all appointments with your doctor and the laboratory. Your heart rhythm should be checked regularly to determine your response to dofetilide. Your doctor will also want to follow your kidney function and blood level of potassium closely while you are taking dofetilide.
If you are ill for more than 24 hours with diarrhea, vomiting, or sweating and have not been able to take in much fluid or nutrition you should call your doctor before taking your next dose of dofetilide.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Last Reviewed: September 1, 2010.