What the FDA labels say about taking them together
Ketoconazole and propafenone
Propafenone's FDA label of September 1, 2025 names ketoconazole in its drug interactions section; the ketoconazole label PlainMeds reads does not name propafenone. The propafenone label: “Drugs that inhibit CYP2D6 and CYP3A4 can be expected to cause increased plasma levels of propafenone.”
Check it at the source: the ketoconazole FDA label on DailyMed (effective January 28, 2026, E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC); the propafenone FDA label on DailyMed (effective September 1, 2025, Strides Pharma Science Limited).
What does the ketoconazole label say about propafenone?
Ketoconazole's label (effective January 28, 2026) does not name propafenone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (ketoconazole), E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC, effective January 28, 2026 (SPL set cad7c647-34a9-4e4e-83b3-8d78e58f588f), via openFDA; the full label on DailyMed
What does the propafenone label say about ketoconazole?
Propafenone label, drug interactionsDrugs that inhibit CYP2D6 (such as desipramine, paroxetine, ritonavir, or sertraline) and CYP3A4 (such as ketoconazole, ritonavir, saquinavir, erythromycin, grapefruit juice) can be expected to cause increased plasma levels of propafenone.
Propafenone label, warnings and precautionsDrugs that inhibit these CYP pathways (such as desipramine, paroxetine, ritonavir, sertraline for CYP2D6; ketoconazole, erythromycin, saquinavir, and grapefruit juice for CYP3A4; and amiodarone and tobacco smoke for CYP1A2) can be expected to cause increased plasma levels of propafenone.
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
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
| Ketoconazole | Propafenone | |
|---|---|---|
| Labeled for | Fungal infections | Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.249 per gram 2% cream | $0.115 per tablet 150 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