What the FDA labels say about taking them together
Etonogestrel and phenytoin
Etonogestrel's FDA label of May 28, 2026 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name etonogestrel. The etonogestrel label: “Some drugs or herbal products that may decrease the effectiveness of HCs include efavirenz, phenytoin, barbiturates, carbamazepine, bosentan, felbamate, griseofulvin, oxcarbazepine, rifampicin, topiramate, rifabutin …”
Check it at the source: the etonogestrel FDA label on DailyMed (effective May 28, 2026, Organon LLC); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the etonogestrel label say about phenytoin?
Etonogestrel label, drug interactionsSome drugs or herbal products that may decrease the effectiveness of HCs include efavirenz, phenytoin, barbiturates, carbamazepine, bosentan, felbamate, griseofulvin, oxcarbazepine, rifampicin, topiramate, rifabutin, rufinamide, aprepitant, and products containing St. John's wort.
Source: FDA drug label (Nexplanon), Organon LLC, effective May 28, 2026 (SPL set 487f8a62-e142-457c-97cc-2e398fde7594), via openFDA; the full label on DailyMed
What does the phenytoin label say about etonogestrel?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name etonogestrel 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
| Etonogestrel | Phenytoin | |
|---|---|---|
| Labeled for | Birth control | 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