What the FDA labels say about taking them together
Leflunomide and warfarin
Leflunomide's FDA label of June 4, 2025 names warfarin in its drug interactions section; the warfarin label PlainMeds reads does not name leflunomide. The leflunomide label: “Effect on Warfarin Coadministration of ARAVA with warfarin requires close monitoring of the international normalized ratio (INR) because teriflunomide, the active metabolite of ARAVA, may decrease peak INR by …”
Check it at the source: the leflunomide FDA label on DailyMed (effective June 4, 2025, sanofi-aventis U.S. LLC); the warfarin FDA label on DailyMed (effective May 29, 2026, Amneal Pharmaceuticals LLC).
What does the leflunomide label say about warfarin?
Leflunomide label, drug interactionsEffect on Warfarin Coadministration of ARAVA with warfarin requires close monitoring of the international normalized ratio (INR) because teriflunomide, the active metabolite of ARAVA, may decrease peak INR by approximately 25%.
Source: FDA drug label (Arava), sanofi-aventis U.S. LLC, effective June 4, 2025 (SPL set 320f63f2-fac3-4aee-aff8-85724e00ef52), via openFDA; the full label on DailyMed
What does the warfarin label say about leflunomide?
Warfarin's label (effective May 29, 2026) does not name leflunomide 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
| Leflunomide | Warfarin | |
|---|---|---|
| Labeled for | Rheumatoid arthritis | Blood clots (DVT and PE), Atrial fibrillation |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.324 per tablet 10 mg tablet | $0.093 per tablet 2 mg tablet |
| Shortage now | A presentation being discontinued | 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