What the FDA labels say about taking them together
Mifepristone and phenytoin
Mifepristone's FDA label of September 25, 2025 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name mifepristone. The mifepristone label: “Avoid co-administration of mifepristone and CYP3A inducers such as rifampin, rifabutin, rifapentin, phenobarbital, phenytoin, carbamazepine, and St. John's wort.”
Check it at the source: the mifepristone FDA label on DailyMed (effective September 25, 2025, Corcept Therapeutics Incorporated); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the mifepristone label say about phenytoin?
Mifepristone label, drug interactionsAvoid co-administration of mifepristone and CYP3A inducers such as rifampin, rifabutin, rifapentin, phenobarbital, phenytoin, carbamazepine, and St. John's wort.
Source: FDA drug label (Mifepristone), Corcept Therapeutics Incorporated, effective September 25, 2025 (SPL set 63c068cd-9370-460f-829b-70e8c7ebe91e), via openFDA; the full label on DailyMed
What does the phenytoin label say about mifepristone?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name mifepristone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Phenytek), Mylan Pharmaceuticals Inc., effective October 15, 2024 (SPL set 0f94c791-8b07-4b41-927e-c9f28bec5f60), 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
| Mifepristone | Phenytoin | |
|---|---|---|
| Labeled for | n/a | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | $0.145 per capsule 100 mg capsule |
| 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