What the FDA labels say about taking them together
Phenytoin and vigabatrin
Phenytoin's FDA label of October 15, 2024 names vigabatrin in its drug interactions section, and vigabatrin's label names phenytoin too. The vigabatrin label: “DRUG INTERACTIONS Decreased phenytoin plasma levels: dosage adjustment may be needed”
Check it at the source: the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.); the vigabatrin FDA label on DailyMed (effective October 20, 2021, Lundbeck Pharmaceuticals LLC).
What does the phenytoin label say about vigabatrin?
Phenytoin label, drug interactionsInteracting Agent: Antiepileptic drugs; Examples: Carbamazepine, vigabatrin
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
What does the vigabatrin label say about phenytoin?
Vigabatrin label, drug interactionsDRUG INTERACTIONS Decreased phenytoin plasma levels: dosage adjustment may be needed
Source: FDA drug label (SABRIL), Lundbeck Pharmaceuticals LLC, effective October 20, 2021 (SPL set a88ac1b4-e2c9-45c0-b321-4785902172e3), 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
| Phenytoin | Vigabatrin | |
|---|---|---|
| Labeled for | Seizures and epilepsy | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.145 per capsule 100 mg capsule | n/a |
| Shortage now | No current entry | A presentation being discontinued |
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