What the FDA labels say about taking them together
Fluorouracil and warfarin
Fluorouracil's FDA label of January 19, 2026 names warfarin in its drug interactions section; the warfarin label PlainMeds reads does not name fluorouracil. The fluorouracil label: “Discontinue fluorouracil until resolved or decreased to Grade 1, then resume at a reduced dose. Increased Risk of Elevated INR with Warfarin:”
Check it at the source: the fluorouracil FDA label on DailyMed (effective January 19, 2026, Eugia US LLC); the warfarin FDA label on DailyMed (effective May 29, 2026, Amneal Pharmaceuticals LLC).
What does the fluorouracil label say about warfarin?
Fluorouracil label, drug interactionsDRUG INTERACTIONS 7.1 Anticoagulants and CYP 2C9 Substrates Elevated coagulation times have been reported in patients taking fluorouracil concomitantly with warfarin.
Fluorouracil label, warnings and precautionsDiscontinue fluorouracil until resolved or decreased to Grade 1, then resume at a reduced dose. ( 5.8 ) Increased Risk of Elevated INR with Warfarin:
Source: FDA drug label (FLUOROURACIL), Eugia US LLC, effective January 19, 2026 (SPL set 697816ce-dc05-4943-b7f0-2f0b125e93b7), via openFDA; the full label on DailyMed
What does the warfarin label say about fluorouracil?
Warfarin's label (effective May 29, 2026) does not name fluorouracil in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Warfarin Sodium), Amneal Pharmaceuticals LLC, effective May 29, 2026 (SPL set 558b7a0d-5490-4c1b-802e-3ab3f1efe760), 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
| Fluorouracil | Warfarin | |
|---|---|---|
| Labeled for | Colorectal cancer | Blood clots (DVT and PE), Atrial fibrillation |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.616 per gram 5% cream | $0.093 per tablet 2 mg tablet |
| 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