What the FDA labels say about taking them together
Propafenone and warfarin
Propafenone's FDA label of September 1, 2025 names warfarin in its drug interactions section, and warfarin's label names propafenone too. The propafenone label: “The concomitant administration of propafenone and warfarin increased warfarin plasma concentrations at steady state by 39% in healthy volunteers and prolonged the prothrombin time (PT) in patients taking warfarin.”
Check it at the source: the propafenone FDA label on DailyMed (effective September 1, 2025, Strides Pharma Science Limited); the warfarin FDA label on DailyMed (effective May 29, 2026, Amneal Pharmaceuticals LLC).
What does the propafenone label say about warfarin?
Propafenone label, drug interactionsThe concomitant administration of propafenone and warfarin increased warfarin plasma concentrations at steady state by 39% in healthy volunteers and prolonged the prothrombin time (PT) in patients taking warfarin.
Source: FDA drug label (PROPAFENONE HYDROCHLORIDE), Strides Pharma Science Limited, effective September 1, 2025 (SPL set c65253ab-937f-4982-b841-69c2b9f9ccdb), via openFDA; the full label on DailyMed
What does the warfarin label say about propafenone?
Warfarin label, drug interactionsClosely monitor INR if a concomitant drug is a CYP2C9, 1A2, and/or 3A4 inhibitor or inducer. Examples of CYP450 Interactions with Warfarin Enzyme Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil …
Source: FDA drug label (Warfarin Sodium), Amneal Pharmaceuticals LLC, effective May 29, 2026 (SPL set 558b7a0d-5490-4c1b-802e-3ab3f1efe760), 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
| Propafenone | Warfarin | |
|---|---|---|
| Labeled for | Atrial fibrillation | Blood clots (DVT and PE), Atrial fibrillation |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.115 per tablet 150 mg tablet | $0.093 per tablet 2 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