What the FDA labels say about taking them together
Dienogest/estradiol and phenytoin
Dienogest/estradiol's FDA label of June 26, 2024 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name dienogest/estradiol. The dienogest/estradiol label: “CYP3A4 induction: Women taking strong CYP3A4 inducers should not choose Natazia as their oral contraceptive due to the possibility of decreased contraceptive efficacy.”
Check it at the source: the dienogest/estradiol FDA label on DailyMed (effective June 26, 2024, Bayer HealthCare Pharmaceuticals Inc.); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the dienogest/estradiol label say about phenytoin?
Dienogest/estradiol label, drug interactionsSome drugs or herbal products that may decrease the effectiveness of hormonal contraceptives include phenytoin, barbiturates, carbamazepine, bosentan, felbamate, griseofulvin, oxcarbazepine, rifampin, topiramate and products containing St. John’s wort.
Dienogest/estradiol label, warnings and precautionsCYP3A4 induction: Women taking strong CYP3A4 inducers (for example, carbamazepine, phenytoin, rifampicin, and St. John’s wort) should not choose Natazia as their oral contraceptive due to the possibility of decreased contraceptive efficacy.
Source: FDA drug label (Natazia), Bayer HealthCare Pharmaceuticals Inc., effective June 26, 2024 (SPL set 02c91fba-9c47-43ef-ac78-e82369798834), via openFDA; the full label on DailyMed
What does the phenytoin label say about dienogest/estradiol?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name dienogest/estradiol 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
| Dienogest/estradiol | Phenytoin | |
|---|---|---|
| Labeled for | Birth control | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $8.46 per tablet 28 tablet | $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