What the FDA labels say about taking them together
Nelfinavir and warfarin
Nelfinavir's FDA label of December 11, 2025 names warfarin in its drug interactions section, and warfarin's label names nelfinavir too. The nelfinavir label: “Coadministration of warfarin and VIRACEPT may affect concentrations of warfarin. It is recommended that the INR be monitored carefully during treatment with VIRACEPT, especially when commencing therapy.”
Check it at the source: the nelfinavir FDA label on DailyMed (effective December 11, 2025, AGOURON); the warfarin FDA label on DailyMed (effective May 29, 2026, Amneal Pharmaceuticals LLC).
What does the nelfinavir label say about warfarin?
Nelfinavir label, drug interactionsConcomitant Drug Class/Drug Name: Warfarin; Effect on Concentration: Warfarin; Clinical Comment: Coadministration of warfarin and VIRACEPT may affect concentrations of warfarin. It is recommended that the INR (international normalized ratio) be monitored carefully during treatment with VIRACEPT, especially when commencing therapy.
Source: FDA drug label (VIRACEPT), AGOURON, effective December 11, 2025 (SPL set e72c2bc6-9462-4a2e-8e1d-b97592376cbd), via openFDA; the full label on DailyMed
What does the warfarin label say about nelfinavir?
Warfarin label, drug interactions… clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole, ranitidine, ranolazine, ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil, nafcillin, phenytoin, pioglitazone, prednisone, rifampin, rufinamide
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
| Nelfinavir | Warfarin | |
|---|---|---|
| Labeled for | HIV | Blood clots (DVT and PE), Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $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