What the FDA labels say about taking them together
Varenicline and warfarin
Varenicline's FDA label of January 23, 2026 names warfarin in its drug interactions section; the warfarin label PlainMeds reads does not name varenicline. The varenicline label: “Effect of Smoking Cessation on Other Drugs: Pharmacokinetics or pharmacodynamics of certain drugs may be altered, necessitating dose adjustment.”
Check it at the source: the varenicline FDA label on DailyMed (effective January 23, 2026, Pfizer Laboratories Div Pfizer Inc); the warfarin FDA label on DailyMed (effective May 29, 2026, Amneal Pharmaceuticals LLC).
What does the varenicline label say about warfarin?
Varenicline label, drug interactionsEffect of Smoking Cessation on Other Drugs: Pharmacokinetics or pharmacodynamics of certain drugs (e.g., theophylline, warfarin, insulin) may be altered, necessitating dose adjustment.
Source: FDA drug label (CHANTIX), NDA021928 (Pf Prism Cv), as published by Pfizer Laboratories Div Pfizer Inc, effective January 23, 2026 (SPL set f0ff4f27-5185-4881-a749-c6b7a0ca5696), via openFDA; the full label on DailyMed
What does the warfarin label say about varenicline?
Warfarin's label (effective May 29, 2026) does not name varenicline 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
| Varenicline | Warfarin | |
|---|---|---|
| Labeled for | Quitting smoking | Blood clots (DVT and PE), Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.316 per tablet 1 mg tablet | $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