What the FDA labels say about taking them together
Phenytoin and vemurafenib
Vemurafenib's FDA label of August 28, 2026 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name vemurafenib. The vemurafenib label: “Avoid coadministration of ZELBORAF with strong CYP3A4 inducers, and replace these drugs with alternative drugs when possible.”
Check it at the source: the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.); the vemurafenib FDA label on DailyMed (effective August 28, 2026, Genentech, Inc.).
What does the phenytoin label say about vemurafenib?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name vemurafenib 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 vemurafenib label say about phenytoin?
Vemurafenib label, drug interactionsAvoid coadministration of ZELBORAF with strong CYP3A4 inducers (e.g., phenytoin, carbamazepine, rifampin), and replace these drugs with alternative drugs when possible.
Source: FDA drug label (ZELBORAF), NDA202429 (Hoffmann La Roche), as published by Genentech, Inc., effective August 28, 2026 (SPL set 38eea320-7e0c-485a-bc30-98c3c45e2763), 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 | Vemurafenib | |
|---|---|---|
| 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