Flecainide: Side Effects, Uses & Monitoring
In patients without structural heart disease, flecainide is indicated for the prevention of - paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal reentrant tachycardia, atrioventricular reen
- Data source
- FDA labeling via NIH DailyMed (label d462d58e…)
- Label version
- current
- Last reviewed
- 2026
Reported adverse reactions
Reactions listed in current FDA labeling, with the highest frequency reported across summarized placebo-controlled trials.
| Adverse reaction (as reported in labeling) | Reported frequency* |
|---|---|
| Dizziness* | 18.9% |
| Visual disturbances† | 18% |
| Dyspnea | 10.3% |
| Headache | 9.6% |
| Nausea | 8.9% |
| Fatigue | 7.7% |
| Palpitation | 7% |
| Chest pain | 5.4% |
| Asthenia | 4.9% |
| Tremor | 4.7% |
| Constipation | 4.4% |
| Edema | 3.5% |
| Abdominal pain | 3.3% |
*Highest percentage reported for the active moiety across placebo-controlled trial tables in current FDA labeling. Values reflect trial reporting, not your individual risk.
Labeled uses (from FDA prescribing information)
In patients without structural heart disease, flecainide is indicated for the prevention of - paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia and other supraventricular tachycardias of unspecified mechanism associated with disabling symptoms - paroxysmal atrial fibrillation/flutter (PAF) associated with disabling symptoms. Flecainide is also indicated for the prevention of - documented ventricular arrhythmias, such as sustained ventricular tachycardia (sustained VT), that in the judgment of the physician, are life-threatening. Use of flecainide for the treatment of sustained VT, like other antiarrhythmics, should be initiated in the hospital. The use of flecainide is not recommended in patients with less severe ventricular arrhythmias even if the patients are symptomatic. Because of the proarrhythmic effects of flecainide, its use should be reserved for patients in whom, in the opinion of the physician, the benefits of treatment outweigh the risks. Flecainide should not be used in patients with recent myocardial infarction (see Boxed WARNINGS ). Use of flecainide in chronic atrial fibril…
Conditions associated with Flecainide in labeling
Atrial Fibrillation
An irregular and often rapid heart rhythm that increases the risk of stroke, heart failure, and other heart co...
Coronary Artery Disease
Narrowing of the coronary arteries by plaque, reducing blood flow to the heart muscle and causing chest pain, ...
Myocardial Infarction
A heart attack, occurring when blood flow to part of the heart muscle is blocked, causing chest pain and heart...
Frequently Asked Questions
What is Flecainide used for?
FDA labeling lists the approved uses shown above under "Labeled uses." This summary is informational; only a qualified prescriber can determine whether a medication is appropriate for you.
What are the most commonly reported side effects of Flecainide?
The table above shows adverse reactions and the highest frequencies reported in placebo-controlled trials summarized in current FDA labeling for Flecainide. Individual risk varies.
Does Flecainide require lab monitoring?
Monitoring needs vary. Ask your healthcare provider whether any lab tests apply while taking Flecainide.
Where does this information come from?
All clinical facts on this page were extracted from the current FDA-registered product labeling for this ingredient, published by manufacturers through NIH DailyMed. See the source link below.
Medical disclaimer: Educational content extracted from public FDA labeling. Not medical advice. Always consult a qualified healthcare professional before starting, stopping, or changing any medication.