What the FDA labels say about taking them together
Cyclophosphamide and warfarin
Cyclophosphamide's FDA label of January 19, 2026 names warfarin in its drug interactions section; the warfarin label PlainMeds reads does not name cyclophosphamide. The cyclophosphamide label: “Coumarins Both increased and decreased warfarin effect have been reported in patients receiving warfarin and cyclophosphamide.”
Check it at the source: the cyclophosphamide FDA label on DailyMed (effective January 19, 2026, Amneal Pharmaceuticals LLC); the warfarin FDA label on DailyMed (effective May 29, 2026, Amneal Pharmaceuticals LLC).
What does the cyclophosphamide label say about warfarin?
Cyclophosphamide label, drug interactionsCoumarins Both increased and decreased warfarin effect have been reported in patients receiving warfarin and cyclophosphamide.
Source: FDA drug label (Cyclophosphamide), Amneal Pharmaceuticals LLC, effective January 19, 2026 (SPL set 520bfe39-dfd5-4a20-9a37-80078afded0d), via openFDA; the full label on DailyMed
What does the warfarin label say about cyclophosphamide?
Warfarin's label (effective May 29, 2026) does not name cyclophosphamide 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
| Cyclophosphamide | Warfarin | |
|---|---|---|
| Labeled for | Leukemia, lymphoma and myeloma | Blood clots (DVT and PE), Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.67 per capsule 50 mg capsule | $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