Sertraline and Flecainide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Sertraline
No brand names on recordFlecainide
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of QT interval prolongation, an increased flecainide exposure and risk for toxicity (cardiac arrhythmia)
Interaction Deep Dive
Avoid coadministration of sertraline and flecainide as this may result in an increased risk of QT prolongation and/or ventricular arrhythmias. Concomitant use of flecainide (a CYP2D6 substrate)2 and sertraline (a CYP2D6 inhibitor) may increase exposure of the CYP2D6 substrate and risk for toxicity. Dose reduction of flecainide may be required. Conversely, an increase in dosage of a flecainide may be needed if sertraline is discontinued 1.
Why it happens (mechanism)
Additive QT interval prolongation; inhibition of CYP2D6-mediated flecainide metabolism by sertraline
Common questions
Can I take Sertraline and Flecainide together?
An increased risk of QT interval prolongation, an increased flecainide exposure and risk for toxicity (cardiac arrhythmia) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Sertraline and Flecainide interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
- Switching Between Generic Sertraline Brands: What to Know
- Is Ashwagandha Safe With Bupropion, Sertraline And Azelastine?
- Converting Doses Of Lexapro (Escitalopram) To Zoloft (Sertraline)
- Is the Magnesium Stearate in Flecainide Animal or Vegetable Based?
- Is It Safe to Take Lutein and Zeaxanthin With Flecainide?
- Is Black Seed Oil Safe With Metoprolol And Flecainide?
Questions for your pharmacist
- Does my dose of Sertraline or Flecainide need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: ZOLOFT oral tablets, oral solution, sertraline hydrochloride oral tablets, oral solution. Viatris Specialty LLC (per FDA), Morgantown, WV, 2023. DailyMed
- Funck-Brentano C, Becquemont L, Kroemer HK, et al: Variable disposition kinetics and electrocardiographic effects of flecainide during repeated dosing in humans: contribution of genetic factors, dose-dependent clearance, and interaction with amiodarone. Clin Pharmacol Ther 1994; 55(3):256-269. PubMed
Keep reading about Sertraline
Keep reading about Flecainide
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist