What the FDA labels say about taking them together
Phenytoin and stiripentol
Stiripentol's FDA label of April 27, 2026 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name stiripentol. The stiripentol label: “… co-administered with a potent CYP1A2, CYP3A4, or CYP2C19 inducer, such as rifampin, phenytoin, phenobarbital and carbamazepine, as these enzymes all metabolize stiripentol.”
Check it at the source: the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.); the stiripentol FDA label on DailyMed (effective April 27, 2026, BIOCODEX, INC.).
What does the phenytoin label say about stiripentol?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name stiripentol 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
What does the stiripentol label say about phenytoin?
Stiripentol label, drug interactionsDrugs on DIACOMIT Induction-based interactions leading to decreases in DIACOMIT concentrations are possible when co-administered with a potent CYP1A2, CYP3A4, or CYP2C19 inducer, such as rifampin, phenytoin, phenobarbital and carbamazepine, as these enzymes all metabolize stiripentol.
Source: FDA drug label (Diacomit), BIOCODEX, INC., effective April 27, 2026 (SPL set 58304ba8-9779-4658-811e-94ffe08c3f16), 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 | Stiripentol | |
|---|---|---|
| Labeled for | Seizures and epilepsy | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.145 per capsule 100 mg capsule | n/a |
| 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