What the FDA labels say about taking them together
Perampanel and phenytoin
Perampanel's FDA label of September 1, 2024 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name perampanel. The perampanel label: “DRUG INTERACTIONS Contraceptives: 12 mg once daily may decrease the effectiveness of hormonal contraceptives containing levonorgestrel Moderate and Strong CYP3A4 Inducers: increase clearance of perampanel and decrease …”
Check it at the source: the perampanel FDA label on DailyMed (effective September 1, 2024, Teva Pharmaceuticals, Inc.); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the perampanel label say about phenytoin?
Perampanel label, drug interactionsDRUG INTERACTIONS Contraceptives: 12 mg once daily may decrease the effectiveness of hormonal contraceptives containing levonorgestrel ( 7.1 ) Moderate and Strong CYP3A4 Inducers (including carbamazepine, oxcarbazepine, and phenytoin): increase clearance of perampanel and decrease perampanel plasma concentrations.
Source: FDA drug label (Perampanel), Teva Pharmaceuticals, Inc., effective September 1, 2024 (SPL set bc8f7cf2-c19c-4235-859f-9ff1dd21908e), via openFDA; the full label on DailyMed
What does the phenytoin label say about perampanel?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name perampanel 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
| Perampanel | Phenytoin | |
|---|---|---|
| Labeled for | Seizures and epilepsy | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $14.43 per tablet 4 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