In a study of people who had experienced heart attacks within the past 2 years, people who took flecainide were more likely to have another heart attack or to die than people who did not take flecainide. There is not enough information to tell whether taking flecainide also increases the risk of heart attack or death in people who have not had heart attacks within the past 2 years. Because of this serious risk and because flecainide has not been shown to help people with irregular heartbeats to live longer, flecainide should be used only to treat people with life-threatening irregular heartbeats.
Tell you doctor if you have atrial fibrillation or atrial flutter (conditions in which the upper chambers of the heart do not beat effectively). People with atrial fibrillation or atrial flutter who take flecainide may have a higher risk of developing certain types of irregular heartbeats.
Talk to your doctor about the risks of taking flecainide.
Flecainide is used to prevent certain types of life-threatening irregular heartbeats. Flecainide is in a class of medications called antiarrhythmics. It works by slowing electrical signals in the heart to stabilize the heart rhythm.
Flecainide comes as a tablet to take by mouth. It is usually taken once every 12 hours. Some people may take flecainide once every 8 hours if they experience side effects or if their condition cannot be controlled by taking flecainide every 12 hours. Take flecainide at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take flecainide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
You may be hospitalized when you begin your treatment with flecainide. Your doctor will monitor you carefully during this time and for as long as you continue to take flecainide. Your doctor will probably start you on a low dose of flecainide and gradually increase your dose, not more than once every 4 days. Your doctor may also decrease your dose once your condition is controlled.
Flecainide may control your condition, but will not cure it. Continue to take flecainide even if you feel well. Do not stop taking flecainide without talking to your doctor. If you suddenly stop taking flecainide, your condition may become worse.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking flecainide,
- tell your doctor and pharmacist if you are allergic to flecainide or any other medications.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: acetazolamide (Diamox); amiodarone (Cordarone, Pacerone); ammonium chloride; antacids; beta blockers such as atenolol (Tenormin), labetalol (Trandate), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), and propranolol (Inderal); carbamazepine (Carbatrol, Tegretol); cimetidine (Tagamet); clozapine (Clozaril); dichlorphenamide; digoxin (Lanoxin); diltiazem (Cardizem, Tiazac); disopyramide (Norpace); methazolamide; nifedipine (Adalat, Procardia); phenytoin (Dilantin); phenobarbital; quinidine; sodium bicarbonate (baking soda, Citrocarbonate, Soda Mint); and verapamil (Calan, Verelan). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have heart block (condition in which electrical signals are not passed normally from the upper chambers of the heart to the lower chambers). Your doctor may tell you not to take flecainide.
- tell your doctor if you have a pacemaker (device that is surgically placed under the skin to control irregular heartbeats) and if you have or have ever had a heart attack, heart failure, or any type of heart disease; low or high levels of potassium in the blood; or liver or kidney disease. Also tell your doctor if you follow a strict vegetarian diet.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking flecainide, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking flecainide.
- if you are giving this medication to an infant, be sure to talk to the doctor if there will be any major changes in the amount of milk the infant drinks. Milk can affect how the medication is absorbed in the body.
Unless your doctor tells you otherwise, continue your normal diet.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Flecainide may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- changes in vision
- uncontrollable shaking of a part of your body
- stomach pain
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:
- fast, pounding, or irregular heartbeat
- chest pain
- shortness of breath
- extreme tiredness
- loss of appetite
- persistent cough with blood-tinged mucus
- swelling of the hands, feet, ankles, or lower legs
- unusual bleeding or bruising
- pain in the upper right part of the stomach
- yellowing of the skin or eyes
- flu-like symptoms
Flecainide may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
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.
Symptoms of overdose may include:
- slow, fast, or irregular heartbeat
- loss of consciousness
- sudden death
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to flecainide.
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.