What the FDA labels say about taking them together
Capecitabine and phenytoin
Capecitabine's FDA label of February 5, 2026 names phenytoin in its drug interactions section, and phenytoin's label names capecitabine too. The capecitabine label: “Monitor INR more frequently and dose adjust oral vitamin K antagonist as appropriate Phenytoin:”
Check it at the source: the capecitabine FDA label on DailyMed (effective February 5, 2026, H2-Pharma, LLC); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the capecitabine label say about phenytoin?
Capecitabine label, drug interactionsMonitor INR more frequently and dose adjust oral vitamin K antagonist as appropriate Phenytoin:
Source: FDA drug label (XELODA), NDA020896 (Cheplapharm), as published by H2-Pharma, LLC, effective February 5, 2026 (SPL set e702d84d-7162-4751-bf37-d724cc7e45a5), via openFDA; the full label on DailyMed
What does the phenytoin label say about capecitabine?
Phenytoin label, drug interactionsInteracting Agent: Antineoplastic agents; Examples: Capecitabine, fluorouracil
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
| Capecitabine | Phenytoin | |
|---|---|---|
| Labeled for | Colorectal cancer, Breast cancer | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.456 per tablet 500 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