Flecainide

What is Flecainide?

Flecainide is a medication available under the brand name Tambocor, as well as in generic form. It belongs to a class of drugs known as antiarrhythmics, specifically a Class IC antiarrhythmic.

Flecainide is approved for:

• Preventing and treating certain paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal reentrant tachycardia and atrioventricular reentrant tachycardia, in patients without structural heart disease
• Preventing paroxysmal atrial fibrillation/flutter associated with disabling symptoms, in patients without structural heart disease
• Treating certain life-threatening sustained ventricular arrhythmias, in patients who meet specific clinical criteria

Flecainide is available in the following formulation:

• Oral tablets (commonly available in 50 mg, 100 mg, and 150 mg strengths)

Important Note

Flecainide is generally reserved for patients without significant underlying structural heart disease (such as prior heart attack, significant coronary artery disease, or reduced heart pumping function), because of an increased risk of serious, sometimes fatal, heart rhythm problems when used in these populations (see Section 7).

What is the Recommended Dosage of Flecainide?

There is no single “correct” dose of flecainide for everyone. The right dose depends on several individual factors, including:

• The specific arrhythmia being treated
• Kidney and liver function, since flecainide is eliminated through both pathways
• The patient’s age
• Other medications currently being taken
• Response and tolerability, since dose adjustments are typically made gradually with monitoring

Available Dosage Forms

Flecainide is available as oral tablets in a range of strengths, generally taken twice daily, with dose increases made gradually and cautiously under close monitoring, often including periodic ECG (electrocardiogram) checks.

Important Note on Dosing

Exact dosing instructions are not provided on this page because appropriate dosing must be determined individually and requires careful, monitored titration due to the medication’s narrow margin between effective and potentially harmful doses. Patients should:

• Follow the exact dose and schedule prescribed by their licensed medical specialist
• Never adjust the dose on their own
• Attend all recommended monitoring appointments, including ECGs, especially when starting treatment or after a dose change
• Never stop taking flecainide abruptly without consulting their prescriber
• Ask their prescriber or pharmacist if dosing instructions are unclear

How Flecainide Works

Flecainide works by blocking specific channels in heart muscle cells that carry sodium, which slows the electrical signals that travel through the heart. This can help prevent or stop abnormal, rapid heart rhythms originating from certain electrical pathways.

In simple terms: flecainide helps stabilize the heart’s electrical activity, which can prevent episodes of a fast or irregular heartbeat from starting, or help the heart return to a normal rhythm.

Flecainide manages the symptoms and episodes of certain heart rhythm disorders; it does not cure the underlying electrical pathway abnormality causing the arrhythmia, and treatment decisions must carefully weigh its benefits against its own risk of causing new or worsened arrhythmias in certain patients.

Is a Prescription Required to Buy Flecainide Online?

Yes. Flecainide is a prescription-only medication in the United States and most other countries.

Before starting flecainide, patients should consult a licensed medical specialist, such as:

• A cardiologist, ideally one with expertise in heart rhythm disorders (electrophysiologist)

Important Safety Warning

Patients should be cautious of websites offering flecainide without a prescription. These may include:

• Counterfeit medications with incorrect, unsafe, or no active ingredient
• Products not manufactured under proper quality and safety standards, which is a particular concern for an antiarrhythmic medication with a narrow safety margin

Always obtain flecainide from a licensed pharmacy, and only after being evaluated and prescribed by a qualified healthcare provider, typically following careful cardiac evaluation to rule out structural heart disease.

Side Effects of Flecainide

Common Side Effects

These are generally mild and may resolve on their own:

• Dizziness
• Visual disturbances, such as blurred vision or seeing spots
• Headache
• Nausea
• Fatigue

Serious Side Effects

Although uncommon, seek immediate medical attention if any of the following occur:

• New, worsening, or different palpitations, a rapid or irregular heartbeat, or fainting, which may indicate a new or worsened arrhythmia caused by the medication itself (a phenomenon called proarrhythmia)
• Signs of worsening heart failure, such as increased shortness of breath, swelling in the legs or abdomen, or rapid weight gain
• Chest pain
• Signs of an allergic reaction, such as swelling of the face, lips, tongue, or throat, hives, or difficulty breathing

This list is not exhaustive. Patients experiencing any unusual or concerning symptoms, especially new or different heart rhythm sensations, should contact their prescriber promptly or seek emergency care.

Drug Interactions

Flecainide can interact with a range of substances. Patients should tell their prescriber about all medications and products they use, including:

• Other antiarrhythmic medications, since combined use can increase the risk of serious rhythm disturbances
• Beta-blockers and certain calcium channel blockers, since combined use may excessively slow the heart or reduce its pumping ability, though these are sometimes used together intentionally under specialist guidance
• Amiodarone, since it can significantly raise flecainide levels and typically requires a flecainide dose reduction
• Certain antidepressants and antipsychotics, some of which can increase flecainide levels or add to rhythm-related risks
• CYP2D6 inhibitors (such as certain antidepressants like fluoxetine or paroxetine, or the antihistamine diphenhydramine at higher exposure), which can raise flecainide levels
• Other blood thinners, since some interactions may affect bleeding risk indirectly through other mechanisms
• Grapefruit juice, which may affect flecainide levels in some patients

Patients should provide their licensed medical specialist and pharmacist with a complete and current list of all prescription drugs, OTC medications, vitamins, and herbal supplements before starting flecainide.

Safety & Important Considerations

• Structural heart disease: Flecainide carries an increased risk of serious, sometimes fatal, arrhythmias (proarrhythmia) in patients with structural heart disease, such as prior heart attack, significant coronary artery disease, or reduced heart pumping function; a thorough cardiac evaluation, often including an echocardiogram and stress testing, is typically required before starting flecainide to rule out these conditions
• Proarrhythmia risk: All antiarrhythmic medications, including flecainide, carry some risk of causing new or worsened heart rhythm problems; this risk is closely monitored, particularly when starting treatment or adjusting the dose
• Kidney and liver disease: Flecainide is eliminated through both the kidneys and liver; dose adjustments and closer monitoring are generally needed with reduced function in either organ
• Pacemakers and certain conduction abnormalities: Flecainide should be used with caution, or may require a functioning pacemaker, in patients with certain underlying conduction system disorders
• Pregnancy and breastfeeding: Should only be used during pregnancy or breastfeeding if the potential benefit justifies the potential risk, as determined by a specialist
• Age-related considerations: Older adults may be more sensitive to side effects and may be more likely to have underlying structural heart disease, which should be carefully assessed
• FDA boxed warning: Flecainide carries a boxed warning regarding an increased risk of death when used in patients with certain types of structural heart disease (based on findings related to this class of medications), reinforcing the importance of thorough cardiac evaluation before use
• Monitoring requirements: Regular ECG monitoring, and sometimes blood level monitoring, is a standard part of safe flecainide use, particularly during initiation and dose adjustments

This medication should only be used for its approved purpose, following thorough cardiac evaluation, as determined by a licensed specialist.

Who This Medication Is For

Flecainide is generally intended for:

• Adults without significant structural heart disease who have certain supraventricular arrhythmias, such as PSVT or symptomatic paroxysmal atrial fibrillation/flutter
• Adults with certain life-threatening ventricular arrhythmias, in specific clinical circumstances determined by a specialist
• Patients who have undergone thorough cardiac evaluation and been determined by a cardiologist or electrophysiologist to be appropriate candidates, given the medication’s risk profile in patients with structural heart disease

Use should always follow an appropriate, thorough clinical evaluation and a specialist’s recommendation.

Who Should Not Take Flecainide

Flecainide may not be appropriate for individuals who:

• Have significant structural heart disease, including prior heart attack, significant coronary artery disease, or reduced heart pumping function (heart failure with reduced ejection fraction)
• Have certain pre-existing heart block or conduction abnormalities, without an appropriately functioning pacemaker
• Have cardiogenic shock
• Have a known allergy to flecainide or any ingredient in the product

This is not a complete list. A full medical history review and cardiac evaluation by a licensed specialist is necessary to determine if flecainide is safe and appropriate.

What to Do If You Miss a Dose

• Take the missed dose as soon as remembered, unless it is close to the time of the next scheduled dose, in which case the missed dose should generally be skipped
• Do not double up or take an extra dose to make up for a missed one
• Try to take flecainide at the same times each day to maintain consistent rhythm control
• Do not stop taking flecainide on your own, even if a dose is missed occasionally, without consulting a prescriber
• Contact a licensed medical specialist if there is any uncertainty about the dosing schedule

Related medications to Flecainide

Other medications used for arrhythmias, depending on the specific type of arrhythmia and presence or absence of structural heart disease, include:

• Propafenone, another Class IC antiarrhythmic with a similar risk profile
• Amiodarone, sotalol, or dofetilide, antiarrhythmics that may be preferred in patients with structural heart disease
• Beta-blockers or calcium channel blockers, for certain arrhythmias
• Catheter ablation, a non-medication procedural option for certain arrhythmias

Switching between treatments should only be done in consultation with a licensed cardiologist or electrophysiologist, who can weigh factors such as the specific arrhythmia, presence of structural heart disease, and overall cardiac function.

Storage Instructions

• Store at room temperature, generally between 68°F and 77°F (20°C to 25°C), unless otherwise directed on the packaging
• Keep away from excess heat, moisture, and direct light
• Store in the original packaging or container until ready to use
• Keep out of reach of children and pets
• Dispose of expired or unused medication according to local guidelines or pharmacist instructions

Disclaimer:

This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Patients must consult a licensed cardiologist or electrophysiologist before starting, changing, or stopping treatment with flecainide. Treatment decisions, including thorough evaluation for underlying structural heart disease, must be based on a full clinical evaluation by a qualified specialist.