What the FDA labels say about taking them together
Dronedarone and phenobarbital
Dronedarone's FDA label of May 29, 2025 names phenobarbital in its drug interactions section; the phenobarbital labels PlainMeds reads (2) do not name dronedarone. The dronedarone label: “Rifampin and Other CYP3A Inducers Avoid rifampin or other CYP3A inducers such as phenobarbital, carbamazepine, phenytoin, and St. John's wort because they decrease exposure to dronedarone significantly.”
Check it at the source: the dronedarone FDA label on DailyMed (effective May 29, 2025, Sanofi-Aventis U.S. LLC); the phenobarbital FDA label on DailyMed (effective August 27, 2026).
What does the dronedarone label say about phenobarbital?
Dronedarone label, drug interactionsRifampin and Other CYP3A Inducers Avoid rifampin or other CYP3A inducers such as phenobarbital, carbamazepine, phenytoin, and St. John's wort because they decrease exposure to dronedarone significantly [see Clinical Pharmacology (12.3) ].
Source: FDA drug label (Multaq), Sanofi-Aventis U.S. LLC, effective May 29, 2025 (SPL set 7fa41601-7fb5-4155-8e50-2ae903f0d2d6), via openFDA; the full label on DailyMed
What does the phenobarbital label say about dronedarone?
Phenobarbital's label (effective August 27, 2026) and its 1 other brand-application label do not name dronedarone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Phenobarbital), Chartwell RX, LLC, effective August 27, 2026 (SPL set 74428144-fb24-40a5-a670-3b876e2d116c), 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
| Dronedarone | Phenobarbital | |
|---|---|---|
| Labeled for | n/a | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $13.19 per tablet 400 mg tablet | $0.213 per tablet 100 mg tablet |
| Shortage now | No current entry | A presentation being discontinued |
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