Highlights for flecainide

  1. Flecainide oral tablet is only available as a generic drug.
  2. Your dosage depends on your age and the condition that you’re treating. Your doctor will decide a dose that’s right for you.
  3. Flecainide is an oral drug that’s used to prevent the following types of abnormal heart rhythms: paroxysmal supraventricular tachycardia (PSVT), paroxysmal atrial fibrillation or flutter (PAF), and ventricular arrhythmias.

FDA warning for heart attack and irregular heart rate

  • This drug has a Black Box Warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients to potentially dangerous effects.
  • If you’ve had a heart attack within the past two years, flecainide may raise your risk of having another heart attack, which can be fatal. This drug should only be used if you have a life-threatening irregular heart rate.
  • Tell your doctor if you have atrial fibrillation or atrial flutter. If you have these conditions where your heart does not beat correctly, you have an increased risk for developing certain types of irregular heartbeats. Flecainide is not recommended if you have chronic atrial fibrillation.
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Other important warnings

  • Abnormal heart rhythm risk. Flecainide can cause new or worsened abnormal heart rhythms. Depending on your condition, your doctor may first give you this medication in the hospital so that your heart rhythms can be closely monitored.
  • Heart failure warning. Flecainide can cause or worsen heart failure. Your doctor will closely monitor the levels of this drug in your body if you have heart failure.

Flecainide oral tablet is a prescription drug that is only available as a generic drug. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand. Talk to your healthcare provider to see if the generic will work for you.

Why it’s used

Flecainide is used to prevent paroxysmal atrial fibrillation, ventricular arrhythmia, and paroxysmal supra ventricular tachycardia. Paroxysmal atrial fibrillation is a condition that causes temporary abnormal heart rate in the upper chambers of your heart. It can cause symptoms such as lightheadedness, chest pain, and shortness of breath. Ventricular arrhythmia is an abnormal heart rhythm that starts in the lower chambers of your heart. Your doctor may give you this drug if they believe that your condition is life threatening. Supra ventricular tachycardia is a condition that causes a temporary increase in your heart rate that starts in the parts of your heart above the ventricles. It can cause symptoms such as shortness of breath, chest tightness, and being able to feel your heart beating.

Flecainide may be used as part of a combination therapy. That means you need to take it with other drugs.

How it works

Flecainide belongs to a class of drugs called antiarrhythmics. A class of drugs refers to medications that work similarly. They have a similar chemical structure and are often used to treat similar conditions.

This drug works by slowing down the electrical signals in your heart. This makes your heart rhythm stable.

Flecainide oral tablet doesn’t cause drowsiness, but it can cause other side effects. Mild side effects may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Most common side effects

The most common side effects that occur with flecainide include:

  • Stomach problems. Symptoms may include:
    • constipation
    • stomach pain
    • nausea
  • Vision problems. Symptoms may include:
    • blurred vision
    • spots in your field of vision
  • Low blood pressure. Symptoms may include:
    • dizziness
    • lightheadedness
    • feeling faint or weak
  • Uncontrollable shaking of parts of your body, such as your hands, arms, head, or legs
  • Headache

Serious side effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 911.

  • Heart failure. Symptoms may include:
    • a buildup of fluid in your arms, legs, hands, or feet
    • unexplained weight gain
  • Abnormal heart rate. Symptoms may include:
    • fluttering heart rate
    • slow heart rate
    • fast heart rate
    • chest pain
    • shortness of breath
  • Liver problems. Symptoms may include:
    • yellowing of your skin or the whites of your eyes
    • loss of appetite
    • weakness
  • Stomach problems. Symptoms may include:
    • severe abdominal pain
    • severe nausea
  • Bleeding issues. Symptoms may include:
    • coughing up blood
    • unexplained bleeding or bruising, or bleeding or bruising that lasts longer than usual
  • Severe allergic reaction. Symptoms may include:
    • wheezing
    • chest tightness
    • itching
    • swelling of your face, lips, tongue, or throat
  • Flu-like symptoms. Symptoms may include:
    • fever
    • chills
    • headache
    • muscle and joint pains
    • tiredness

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

Flecainide oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with flecainide are listed below.

Digoxin

Flecainide will increase the levels of digoxin in your body, but you shouldn’t have an increased risk of side effects.

Heart and blood pressure drugs

  • Beta-blockers, such as propranolol (Ineral LA). Using beta blockers with flecainide will increase the levels of both medications in your body, but you shouldn’t have an increased risk of side effects from either medication.
  • Calcium channel blockers, such as nifedipine and diltiazem. Using these drugs with flecainide is not recommended because the effects of using them together are unknown.
  • Verapamil. Using this drug with flecainide is not recommended because it may slow your heart rate too much.

Drugs for seizures

  • phenytoin
  • phenobarbital
  • carbamazepine

Using these drugs with flecainide may decrease the levels of flecainide in your body. This may cause flecainide not to work as well as it should.

Quinidine

Using this drug with flecainide may increase the levels of flecainide in your body. This may increase your risk of side effects.

Disopyramide

Using this drug with flecainide is not recommended. It may slow your heart rate too much.

Amiodarone

When using this drug with flecainide, your doctor will give you half your normal dose of flecainide and monitor you for side effects. Your doctor must monitor the levels of flecainide in your body before they change your dose.

Heartburn medication

  • cimetidine

This drug will increase the levels of flecainide in your body. This may increase your risk of side effects.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

Flecainide oral tablet drug comes with several warnings.

Allergy warning

Flecainide may cause a severe allergic reaction. Symptoms can include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives

Call 911 or go to the nearest emergency room if you develop these symptoms. Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal.

Alcohol interaction

Your body processes alcohol and this drug in similar ways. That means that if you drink alcohol, this drug might take longer to leave your body. You may also experience worse side effects.

Warnings for people with certain health conditions

For people with a heart attack in the last 2 years: If you’ve had a heart attack within the past two years, flecainide may raise your risk of having another heart attack, which can be fatal. This drug should only be used if you have a life-threatening irregular heart rate.

For people with chronic atrial fibrillation or flutter: Tell your doctor if you have atrial fibrillation or atrial flutter. If you have these conditions where your heart doesn’t beat correctly, you have an increased risk for developing certain types of irregular heartbeats. Flecainide is not recommended if you have chronic atrial fibrillation.

For people with abnormal heart rhythm: Flecainide may cause new or worsened abnormal heart rhythms. Depending on your condition, your doctor may first give you this medication in the hospital so that your heart rhythms can be closely monitored.

For people with sick sinus syndrome: This medication can make your condition worse. If you have sick sinus syndrome, this medication may slow down or stop your heart from beating. Use flecainide with extreme caution if you have sick sinus syndrome.

For people with heart failure: Flecainide may cause or worsen heart failure. Your doctor will closely monitor the levels of this drug in your body if you have heart failure.

For people with cardiac conduction abnormalities: Flecainide works by slowing the electrical signals in your heart. If the levels of medication are too high in your body, it can slow the signaling of your heart too much and lead to an increased risk of side effects.

For people with high or low potassium levels: Having too much or not enough potassium in your body can affect how well flecainide works. Your doctor will do a blood test to make sure that you have normal potassium levels before you start taking flecainide.

For people with pacemakers or pacing electrodes: Flecainide should be used with caution if you have a permanent pacemaker or temporary pacing electrodes. This drug can lower the effect of these devices on controlling your heart rhythm.

For people with changes in urine pH: The pH level of your urine (basic or acidic) can increase or decrease the levels of the medication in your body. These changes can either increase your risk of side effects or lower the effect of the medication. Your doctor will do a simple urine test to check the pH level of your urine.

For people with liver problems: Don’t take this drug if you have liver problems unless your doctor tells you to. If your doctor starts you on flecainide, the levels of the medication in your body will be monitored regularly before your doctor changes your dose.

Warnings for other groups

For pregnant women: Flecainide is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Tell your doctor if you’re pregnant or plan to become pregnant. Flecainide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

For women who are breastfeeding

Flecainide passes through breast milk and can cause serious side effects in your child. You and your doctor may need to decide if you’ll take flecainide or breastfeed.

For seniors: Older adults may process this drug more slowly.

For children: The safety and effectiveness of flecainide haven’t been established for use in people younger than 18 years old.

This dosage information is for flecainide oral tablet. All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Forms and strengths

Generic: Flecainide

  • Form: Oral tablet
  • Strengths: 50 mg, 100 mg, and 150 mg

Dosage for prevention of paroxysmal atrial fibrillation or flutter

Adult dosage (ages 18-64 years)

  • Starting dose is 50 mg taken every 12 hours.
  • Your doctor may increase your dose by 50 mg, taken twice per day every 4 days until the drug is effective.

Child dosage (ages 0-17 years)

The safety and effectiveness of flecainide have not been established for use in people younger than 18 years old.

Senior dosage (ages 65 years and older)

Your body may process this drug more slowly. Your doctor may start you on a lowered dose so that too much of this drug doesn’t build up in your body. Too much of the drug in your body can be toxic.

Special considerations

  • Kidney problems:
    • Severe kidney disease: 100 mg taken once per day (or 50 mg taken twice per day). The levels of flecainide in your body must be monitored before any dose changes.
    • Mild and moderate kidney disease: 100 mg every 12 hours. Dosage changes shouldn’t be made more often than every 5 days. The levels of flecainide in your body must be monitored before any dosage changes.
  • Liver problems: Flecainide shouldn’t be used in people with liver problems unless your doctor tells you to. If your doctor starts you on flecainide, the levels of the medication in your body must be monitored before any dose changes.
  • People who also take amiodarone: If you’re taking amiodarone with flecainide, your doctor will give you half of your normal dose of flecainide and watch you for side effects. Your doctor must monitor the levels of flecainide in your body regularly before any dose changes.

Dosage for the prevention of ventricular arrhythmias

Adult dosage (ages 18-64 years)

  • Starting dose is 100 mg taken every 12 hours.
  • Your doctor may increase your dose by 50 mg taken twice per day every 4 days until the drug is effective. Most people don’t need doses higher than 150 mg taken every 12 hours.
  • The maximum dose is 400 mg per day.

Child dosage (ages 0-17 years)

The safety and effectiveness of flecainide have not been established for use in people younger than 18 years old.

Senior dosage (ages 65 years and older)

Your body may process this drug more slowly. Your doctor may start you on a lowered dose so that too much of this drug doesn’t build up in your body. Too much of the drug in your body can be toxic.

Special considerations

  • Kidney problems:
    • Severe kidney disease: 100 mg taken once per day (or 50 mg taken twice per day). The levels of flecainide in your body must be monitored before any dose changes.
    • Mild and moderate kidney disease: 100 mg every 12 hours. Dosage changes shouldn’t be made more often than every 5 days. The levels of flecainide in your body must be monitored before any dosage changes.
  • Liver problems: Flecainide shouldn’t be used in people with liver problems unless your doctor tells you to. If your doctor starts you on flecainide, the levels of the medication in your body must be monitored before any dose changes.

People who also take amiodarone: If you’re taking amiodarone with flecainide, your doctor will give you half of your normal dose of flecainide and watch you for side effects. Your doctor must monitor the levels of flecainide in your body regularly before any dose changes.

Dosage for the prevention of paroxysmal supraventricular tachycardia

Adult dosage (ages 18-64 years)

  • Starting dose is 50 mg taken every 12 hours.
  • Your doctor may increase your dose by 50 mg taken twice per day every 4 days until the drug is effective. The maximum dose is 300 mg per day.

Child dosage (ages 0-17 years)

The safety and effectiveness of flecainide have not been established for use in people younger than 18 years old.

Senior dosage (ages 65 years and older)

Your body may process this drug more slowly. Your doctor may start you on a lowered dose so that too much of this drug doesn’t build up in your body. Too much of the drug in your body can be toxic.

Special considerations

  • Kidney problems:
    • Severe kidney disease: 100 mg taken once per day (or 50 mg taken twice per day). The levels of flecainide in your body must be monitored before any dose changes.
    • Mild and moderate kidney disease: 100 mg every 12 hours. Dosage changes shouldn’t be made more often than every 5 days. The levels of flecainide in your body must be monitored before any dosage changes.
  • Liver problems: Flecainide shouldn’t be used in people with liver problems unless your doctor tells you to. If your doctor starts you on flecainide, the levels of the medication in your body must be monitored before any dose changes.

People who also take amiodarone: If you’re taking amiodarone with flecainide, your doctor will give you half of your normal dose of flecainide and watch you for side effects. Your doctor must monitor the levels of flecainide in your body regularly before any dose changes.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Flecainide oral tablet is used for long-term drug treatment. It comes with risks if you don’t take it as prescribed.

If you don’t take it at all: The symptoms of your abnormal heart rhythm may not improve or may get worse.

If you stop taking it suddenly: If your condition got better while you were taking the medication and you stop taking flecainide suddenly, your abnormal heart rhythm may come back.

If you don’t take it on schedule: You may not see a full benefit of this medication for the treatment of your abnormal heart rhythm. If you double up your dose or take it too close to your next scheduled time, you may be at higher risk of serious side effects.

What to do if you miss a dose: If you forget to take your dose, take it as soon as you remember. If it’s just a few hours before the time to take your next dose, then only take one dose at that time. Never try to catch up by taking two doses at once. This could result in toxic side effects.

How to tell if the drug is working:

  • Paroxysmal atrial fibrillation prevention. You may be able to tell if this medication is working if your symptoms of lightheadedness, chest pain, and shortness of breath improve.
  • Ventricular arrhythmia prevention. You may be able to tell if this medication is working if your symptoms of fainting, chest pain, shortness of breath, or fast heart rate improve.
  • Paroxysmal supraventricular tachycardia prevention. You may be able to tell if this medication is working if your symptoms of shortness of breath, chest tightness, and being able to feel your heart beating improve.

Keep these considerations in mind if your doctor prescribes flecainide oral tablet for you.

General

  • Don’t cut or crush the tablet.
  • Not every pharmacy stocks this drug, so call ahead.

Storage

  • Keep in temperatures from 68–77°F (20–25°C).
  • Don’t freeze flecainide.
  • Store it away from light and high temperatures.
  • Store this drug away from moisture and damp locations, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you or in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt this medication.
  • You may need to show your pharmacy’s label to clearly identify the medication. Keep the original prescription label with you when traveling.
  • Don’t leave this medicine in the car, especially when the temperature is hot or freezing.

Clinical monitoring

During your treatment with flecainide, your doctor will monitor the level of the drug in your body. This should be monitored regularly because your risk of side effects increases if your flecainide levels are too high. Your levels should be monitored more closely if you have severe kidney disease, severe liver disease, or congestive heart failure.

Insurance

Many insurance companies will require a prior authorization before they approve the prescription and pay for flecainide.

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.