What the FDA labels say about taking them together
Erythromycin and propafenone
Propafenone's FDA label of September 1, 2025 names erythromycin in its drug interactions section; the erythromycin labels PlainMeds reads (4) do 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 erythromycin FDA label on DailyMed (effective August 1, 2024, Teva Pharmaceuticals USA, Inc.); the propafenone FDA label on DailyMed (effective September 1, 2025, Strides Pharma Science Limited).
What does the erythromycin label say about propafenone?
Erythromycin's label (effective August 1, 2024) and its 3 other brand-application labels do 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 (Erythromycin), Teva Pharmaceuticals USA, Inc., effective August 1, 2024 (SPL set 75a0bd5a-d09f-483b-bfd8-f8343b149eb2), via openFDA; the full label on DailyMed
What does the propafenone label say about erythromycin?
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
| Erythromycin | Propafenone | |
|---|---|---|
| Labeled for | Bacterial infections, Acne | Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.96 per tablet 250 mg tablet | $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