Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Flecainide is an antiarrhythmic of class 1C: it blocks sodium channels in the heart, slowing the electrical signal. It is used to prevent and stop some fast heart rhythms, such as atrial fibrillation and supraventricular tachycardia, in people whose hearts are otherwise structurally healthy. It is sold as Tambocor, among other names.
Flecainide is broken down partly by the liver enzyme CYP2D6 and partly cleared unchanged by the kidneys. People with no working CYP2D6 copies (poor metabolizers) keep higher levels, especially if their kidney function is reduced, and blood levels are often monitored for that reason. DPWG has published a guideline on CYP2D6 and flecainide. A few studies have looked at other genes, with weak evidence.
Clinical guidelines that name a gene for Flecainide. They sort people into groups by the gene copies they carry.
DPWG guideline: CYP2D6. CYP2D6 activity score 0 to 6 or more. 2011.
Every published finding on gene variants and Flecainide. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
CYP2D6 CYP2D6*1, CYP2D6*4, CYP2D6*5, CYP2D6*10, CYP2D6*21, CYP2D6*36: Level 1A · replicated. Metabolism/PK: Cardiac rhythm disease. 4.
SCN4A rs80338792: Level 3. Efficacy: Myotonia. 2.
SCN4A rs1567817380: Level 3. Efficacy: Myotonic Disorders. 1.
SCN4A rs121908547: Level 3. Efficacy: Myotonic Disorders. 1.
Studies of how quickly the body processes this medication.
Studies of how well it worked in people carrying a variant.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
ReadYourDNA provides educational interpretation of DNA data you already have. It is not diagnostic, not a substitute for professional medical advice, diagnosis, or treatment, and is not intended to diagnose, treat, cure, or prevent any disease. Talk to a clinician before acting on any result.
Raw DNA Data Reports for 23andMe & AncestryDNA · About ReadYourDNA · FAQ · Methodology & Science · Pricing · Support and complaints · Legal & Contact · Health Traits · Pharmacogenomics · Carrier Status · Variant Explorer · The Human Karyotype · Privacy Policy · Terms of Service · Accessibility · Consumer Health Data Privacy · Your Privacy Choices · Editorial Standards · Your Data, Checkable · Sample Report · ReadYourDNA and Promethease compared · What is inside a 23andMe raw data file · What is inside an AncestryDNA raw data file · What a chatbot can and cannot do with your raw DNA file · Where a raw DNA file can still be uploaded in 2026
Written, maintained and operated by Martin Pechhacker, sole proprietor, Vienna, Austria. Trade register GISA 40064420. support@readyourdna.com