Flecainide

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

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 is part of the drug class:

• Antiarrhythmics, class Ic

Before taking flecainide, tell your doctor if you are taking any of the following medicines:

• cimetidine (Tagamet),

• digoxin (digitalis, Lanoxin);

• a diuretic (water pill);

• verapamil (Verelan, Calan, Isoptin);

• seizure medication such as carbamazepine (Carbatrol, Tegretol), phenobarbital (Solfoton), or phenytoin (Dilantin);

• other heart rhythm medications such as amiodarone (Cordarone), disopyramide (Norpace), or quinidine (Quinaglute, Quinidex); or

• a beta-blocker such as atenolol (Tenormin), labetalol (Normodyne, Trandate), metoprolol (Lopressor, Toprol), propranolol (Inderal, InnoPran), sotalol (Betapace), timolol (Blocadren), and others.

This list is not complete and there may be other drugs that can interact with flecainide. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

In the U.S.

• Tambocor

Available Dosage Forms:

• Capsule, Extended Release
• Tablet

Therapeutic Class: Antiarrhythmic, Group IC

Chemical Class: Amino Amide

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• Difficult or labored breathing
• dizziness, fainting, or lightheadedness
• fast, irregular, pounding, or racing heartbeat or pulse
• shortness of breath
• tightness in the chest
• wheezing

• Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• chest pain
• fainting
• feeling of warmth
• fever
• increased sweating
• partial or slight paralysis
• redness of the face, neck, arms, and occasionally, upper chest
• shakiness and unsteady walk
• shakiness in the legs, arms, hands, or feet
• swelling of the feet or lower legs
• trembling or shaking of the hands or feet
• unsteadiness, trembling, or other problems with muscle control or coordination

• Arm, back, or jaw pain
• black, tarry stools
• bleeding gums
• blood in the urine or stools
• blurred vision
• chest discomfort
• chest tightness or heaviness
• chills
• confusion
• convulsions
• cough
• decrease in the frequency of urination
• decrease in urine volume
• difficulty in passing urine (dribbling)
• difficulty with breathing
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• frequent urination
• general feeling of discomfort or illness
• headache
• increased volume of pale, dilute urine
• nausea
• nervousness
• noisy breathing
• painful or difficult urination
• pinpoint red spots on the skin
• pounding in the ears
• sensation of pins and needles
• slow or fast heartbeat
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• stabbing pain
• sweating
• swollen glands
• thickening of bronchial secretions
• troubled breathing
• unusual bleeding or bruising
• unusual tiredness or weakness
• yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

• Blurred vision or seeing spots

• Abdominal or stomach pain
• acid or sour stomach
• anxiety or mental depression
• belching
• constipation
• continuing ringing or buzzing or other unexplained noise in the ears
• depression
• diarrhea
• feeling of constant movement of self or surroundings
• general feeling of discomfort or illness
• hearing loss
• heartburn
• indigestion
• lack or loss of strength
• loss of appetite
• sensation of spinning
• sleepiness or unusual drowsiness
• sleeplessness
• skin rash
• stomach discomfort, upset, or pain
• trouble with sleeping
• unable to sleep
• weight loss

• Bloated
• change in color vision
• change in taste
• cracks in the skin
• decreased awareness or responsiveness
• decreased interest in sexual intercourse
• difficulty seeing at night
• difficulty with moving
• dry mouth
• excess air or gas in the stomach or intestines
• eye pain or irritation
• false or unusual sense of well-being
• feeling of unreality
• full feeling
• hair loss or thinning of the hair
• hives or welts
• inability to have or keep an erection
• increased sensitivity of the eyes to sunlight
• itching skin
• joint pain
• lack of feeling or emotion
• loss in sexual ability, desire, drive, or performance
• loss of heat from the body
• loss of memory
• muscle aching or cramping
• muscle pain or stiffness
• passing gas
• problems with memory
• red, swollen skin
• scaly skin
• sense of detachment from self or body
• severe sleepiness
• swollen joints
• swollen lips, mouth, or tongue
• uncaring uncontrolled eye movements

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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

• If you have an allergy to flecainide or any other part of flecainide.
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you have had a recent heart attack.
• If you have heart block.
• If you have any of these health problems: Low potassium or magnesium levels.

This is not a list of all drugs or health problems that interact with this medicine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take flecainide with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

• Tell all of your health care providers that you take this medicine. This includes your doctors, nurses, pharmacists, and dentists.
• Have blood work checked as you have been told by the doctor. Talk with the doctor.
• If you have a pacemaker, talk with your doctor.
• In children with certain heart problems, heart attack and sudden death have happened with flecainide. Talk with the doctor.
• This medicine may need to be started in a hospital where you will be closely watched. Talk with your doctor.
• Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using this medicine while you are pregnant.
• Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

Use flecainide as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• Take with or without food.
• To gain the most benefit, do not miss doses.
• Keep taking this medicine as you have been told by your doctor or other health care provider, even if you feel well.

What do I do if I miss a dose?

• Take a missed dose as soon as you think about it.
• If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
• Do not take 2 doses at the same time or extra doses.

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Chest pain or pressure.
• Very bad dizziness or passing out.
• A new or worse heartbeat that does not feel normal.
• Fast or slow heartbeat.
• Change in eyesight.
• Heart failure has happened with flecainide, as well as heart failure that has gotten worse in people who already have it. Sometimes, this has been deadly. Tell your doctor if you have heart disease. Call your doctor right away if you have shortness of breath, a big weight gain, a heartbeat that is not normal, or swelling in the arms or legs that is new or worse.

• Store at room temperature.
• Store in a dry place. Do not store in a bathroom.
• Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
• Check with your pharmacist about how to throw out unused drugs.

Flecainide acetate tablets are contraindicated in patients with pre-existing second- or third-degree AV block, or with right bundle branch block when associated with a left hemiblock (bifascicular block), unless a pacemaker is present to sustain the cardiac rhythm should complete heart block occur. Flecainide acetate tablets are also contraindicated in the presence of cardiogenic shock or known hypersensitivity to the drug.

Refer to adult dosing.

Initial dose: 50 mg orally every 12 hours.
Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved.

Initial dose: 50 mg orally every 12 hours.
Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved.

CrCl=35 mL/min or less: Initial dose: 100 mg orally once a day or 50 mg twice a day. It may take longer than 4 days before a new steady-state plasma level is reached following a dosage change.

In patients with less severe renal dysfunction: Initial dose: 100 mg every 12 hours.

A series of 14 women who were given flecainide 300 to 400 mg per day to treat fetal supraventricular tachycardias complicated by fetal hydrops and ascites has been reported. The drug was given at a mean gestational age of 31 weeks, and was continued for up to five days. The mean umbilical cord to maternal plasma ratio was 0.80, with fetal concentrations ranging from 400 to 800 mcg per liter. One intrauterine death was observed three days after flecainide was begun, that may have been due to a proarrhythmic effect of flecainide. A second infant died later of sudden infant death syndrome. No adverse effects or problems were noted in the remaining 12 infants. There have been several cases in which flecainide was used safely during human pregnancy. This drug has been used safely and successfully to treat refractory (to digoxin) fetal tachycardia. Average umbilical cord blood to maternal serum flecainide concentration ratios ranging from 0.63 to 0.97 have been reported. However, at least one case of neonatal cardiotoxicity related to maternal use of flecainide for fetal supraventricular tachycardia has been reported.

Flecainide has been assigned to pregnancy category C by the FDA. Animal studies have revealed teratogenicity and embryotoxicity in rabbits that were given doses 30 to 35 mg/kg/day. No data from controlled studies in human pregnancy are available. Flecainide should only be given during pregnancy when there are no alternatives and benefit outweighs risk.

Summary of Use during Lactation

Limited information indicates that maternal doses of flecainide up to 200 mg daily produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. Because of the relative lack of data concerning breastfeeding during maternal flecainide therapy, exclusively breastfed infants should be carefully monitored if this drug is used during lactation, possibly including measurement of serum levels to rule out toxicity if there is a concern.

Drug Levels

Maternal Levels. In one mother taking oral flecainide 100 mg twice daily, milk flecainide levels were 0.89 and 1.09 mg/L 3 hours after the mother's second dose of the day on days 5 and 7 postpartum, respectively.[1] Assuming the measured levels are approximately peak levels, the amounts in milk represent a maximum infant dosage of about 4.5% of the maternal weight-adjusted dosage.

Eleven healthy volunteer women were given oral flecainide 100 mg twice daily (average 3.2 mg/kg daily) for 5.5 days after delivery. Flecainide levels in 24-hour pooled milk samples averaged 0.756 mg/L (range 0.134 to 1.529 mg/L) among the 11 women on day 5 when steady state had been attained. This corresponds to an average infant dosage of 3.6% (range 0.7 to 6.9%) of the maternal weight-adjusted dosage. After the last dose, the half-life of flecainide in breastmilk averaged 14.7 hours.[2]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Relevant published information was not found as of the revision date.

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

References

1. Wagner X, Jouglard J, Moulin M et al. Coadministration of flecainide acetate and sotalol during pregnancy: lack of teratogenic effects, passage across the placenta, and excretion in human breast milk. Am Heart J. 1990;119:700-2. PMID: 1689933

2. McQuinn RL, Pisani A, Wafa S et al. Flecainide excretion in human breast milk. Clin Pharmacol Ther. 1990;48:262-7. PMID: 2119270