Generic name: flecainide [ FLEK-a-nide ]
Brand name: Tambocor
Dosage form: oral tablet (100 mg; 150 mg; 50 mg)
Drug class: Group I antiarrhythmics

Medically reviewed by Drugs.com on Aug 4, 2023. Written by Cerner Multum.

What is flecainide?

Flecainide is a Class IC anti-arrhythmic that is used in certain situations to prevent serious heart rhythm disorders.

Flecainide may also be used for purposes not listed in this medication guide.

Flecainide side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Flecainide may cause serious side effects. Call your doctor at once if you have:

• fast or pounding heartbeats;

• fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out);

• slow heart rate, weak pulse, slow breathing (breathing may stop);

• feeling short of breath;

• swelling, rapid weight gain;

• pale skin, easy bruising or bleeding, unusual weakness;

• fever, flu-like symptoms; or

• jaundice (yellowing of the skin or eyes).

Common side effects of flecainide may include:

• dizziness;

• vision problems;

• trouble breathing;

• headache;

• nausea; or

• feeling weak or tired.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Warnings

You should not use flecainide if you have a serious heart condition such as bundle branch block or AV block (without a pacemaker), or if your heart cannot pump blood properly.

You may receive your first dose in a hospital or clinic setting to quickly treat any serious side effects.

Before taking this medicine

You should not use flecainide if you are allergic to it, or if:

• you have a serious heart condition such as bundle branch block or AV block (unless you have a pacemaker); or

• your heart cannot pump blood properly.

Tell your doctor if you have ever had:

• a heart attack;

• chronic atrial fibrillation, or "AFib";

• congestive heart failure;

• a heart condition called "sick sinus syndrome";

• an electrolyte imbalance (such as low levels of potassium or magnesium in your blood); or

• liver disease.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.

How should I take flecainide?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

You may receive your first few doses in a hospital or clinic setting to quickly treat any serious side effects.

Your heart rate will be monitored using an electrocardiograph or ECG (sometimes called an EKG). This will help your doctor determine how long to treat you with flecainide.

You may also need frequent blood tests to check your liver or kidney function.

Store at room temperature away from moisture, heat, and light.

Flecainide dosing information

Usual Adult Dose for Ventricular Tachycardia:

Initial dose: 100 mg orally every 12 hours.
Maintenance dose: May be increased in increments of 50 mg bid every 4 days until efficacy is achieved. Most patients with SUSTAINED VT do not require more than 150 mg every 12 hours (300 mg/day), and the maximum dose recommended is 400 mg/day.

Usual Adult Dose for Atrial Fibrillation:

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.

Usual Adult Dose for Atrial Flutter:

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.

Usual Adult Dose for Wolff-Parkinson-White Syndrome:

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.

Usual Adult Dose for Paroxysmal Supraventricular Tachycardia:

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.

Usual Pediatric Dose for Supraventricular Tachycardia:

less than 1 month:
Supraventricular tachycardia: Limited data available: Initial: 2 mg/kg/day orally divided every 12 hours; titrate to clinical response, monitor serum concentration; mean dose required to suppress SVT: 3.35 ± 1.35 mg/kg/day in 17 neonates (n=20 treated neonates; mean PNA: 11.5 days; mean GA: 36.8 weeks; mean birthweight: 2.8 kg); study did not report resultant serum concentrations.

1 month or older:
Initial: 1 to 3 mg/kg/day orally or 50 to 100 mg/m2/day orally in 3 divided doses; usual: 3 to 6 mg/kg/day or 100 to 150 mg/m2/day in 3 divided doses; up to 8 mg/kg/day or 200 mg/m2/day for uncontrolled patients with subtherapeutic levels; higher doses have been reported, however they may be associated with an increased risk of proarrhythmias; a review of world literature reports the average effective dose to be 4 mg/kg/day or 140 mg/m2/day.

Related/similar drugs

diltiazem, amiodarone, Xarelto, digoxin, lidocaine, bisoprolol, rivaroxaban, sotalol, phenylephrine, propafenone

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include nausea, vomiting, slow heart rate, fainting, or seizure (convulsions).

What should I avoid while taking flecainide?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect flecainide?

Tell your doctor about all your other medicines, especially:

• digoxin;

• a diuretic or "water pill";

• a beta-blocker (atenolol, metoprolol, propranolol, sotalol, and others);

• other heart medications such as amiodarone, diltiazem, disopyramide, nifedipine, quinidine, or verapamil; or

• seizure medication.

This list is not complete. Other drugs may affect flecainide, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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