What the FDA labels say about taking them together
Norethindrone and phenytoin
Norethindrone's FDA label of January 31, 2026 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name norethindrone. The norethindrone label: “This could result in unintended pregnancy or breakthrough bleeding. Examples include rifampin, barbiturates, phenylbutazone, phenytoin, carbamazepine, felbamate, oxcarbazepine, topiramate, and griseofulvin. b.”
Check it at the source: the norethindrone FDA label on DailyMed (effective January 31, 2026, Glenmark Pharmaceuticals Inc., USA); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the norethindrone label say about phenytoin?
Norethindrone label, drug interactionsSome drugs or herbal products that may decrease the effectiveness of HCs include efavirenz, phenytoin, barbiturates, carbamazepine, bosentan, felbamate, griseofulvin, oxcarbazepine, rifampicin, rifabutin, rufinamide, aprepitant, and products containing St. John’s wort.
Nora Be label (Teva Pharmaceuticals, Inc., April 2, 2024), drug interactionsThis could result in unintended pregnancy or breakthrough bleeding. Examples include rifampin, barbiturates, phenylbutazone, phenytoin, carbamazepine, felbamate, oxcarbazepine, topiramate, and griseofulvin. b.
Source: FDA drug label (Nora Be, NDA017060), Teva Pharmaceuticals, Inc., effective April 2, 2024 (SPL set 426ac898-7745-4645-bf9b-bae319e260e8), via openFDA
Source: FDA drug label (Norethindrone), Glenmark Pharmaceuticals Inc., USA, effective January 31, 2026 (SPL set 0d2f8fea-3675-40d2-afd9-9fcb148dbd4b), via openFDA; the full label on DailyMed
What does the phenytoin label say about norethindrone?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name norethindrone 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
| Norethindrone | Phenytoin | |
|---|---|---|
| Labeled for | Birth control | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.290 per tablet 5 mg 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