What the FDA labels say about taking them together
Flecainide and terbinafine
Terbinafine's FDA label of October 17, 2025 names flecainide in its drug interactions section; the flecainide label PlainMeds reads does not name terbinafine. The terbinafine label: “Drugs predominantly metabolized by the CYP450 2D6 isozyme include the following drug classes: tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers, antiarrhythmics class 1C and monoamine …”
Check it at the source: the flecainide FDA label on DailyMed (effective June 11, 2026, Amneal Pharmaceuticals of New York LLC); the terbinafine FDA label on DailyMed (effective October 17, 2025, PD-Rx Pharmaceuticals, Inc.).
What does the flecainide label say about terbinafine?
Flecainide's label (effective June 11, 2026) does not name terbinafine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Flecainide Acetate), Amneal Pharmaceuticals of New York LLC, effective June 11, 2026 (SPL set ee9595d5-08a1-4529-9215-ddc3c7f929c4), via openFDA; the full label on DailyMed
What does the terbinafine label say about flecainide?
Terbinafine label, drug interactionsDrugs predominantly metabolized by the CYP450 2D6 isozyme include the following drug classes: tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers, antiarrhythmics class 1C (e.g., flecainide and propafenone) and monoamine oxidase inhibitors Type B. Coadministration of Terbinafine tablets should be done with careful monitoring and may require a reduction in dose of the 2D6-metabolized drug.
Source: FDA drug label (Terbinafine Hydrochloride), PD-Rx Pharmaceuticals, Inc., effective October 17, 2025 (SPL set 2df111dc-ecac-4161-9e22-38436eb37c1f), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Flecainide | Terbinafine | |
|---|---|---|
| Labeled for | n/a | Fungal infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.171 per tablet 100 mg tablet | $0.143 per tablet 250 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once