Drug interactions
Voriconazole + Warfarin
Severity: Major
Voriconazole and Warfarin: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Voriconazole increases warfarin exposure, prolonging prothrombin time and raising INR, which increases the risk of bleeding. The effect can appear within days of starting voriconazole and reverses when it is stopped.
What this interaction means in plain words
Voriconazole and Warfarin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Voriconazole belongs to Anti Fungals; Warfarin belongs to Cardiovascular.
Why it happens
Inhibition of CYP2C9 (and CYP3A4) by voriconazole reduces clearance of S-warfarin.
What to do
Monitor INR closely when starting or stopping voriconazole, and reduce the warfarin dose as needed. Watch for signs of bleeding.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
Other interactions of Warfarin
- Defibrotide + Warfarin Contraindicated
- Ketorolac + Warfarin Contraindicated
- Abciximab + Warfarin Major
- Acetylsalicylic acid + Warfarin Major
- Adagrasib + Warfarin Major
- Amiodarone + Warfarin Major
Frequently asked questions
Can I take Voriconazole with Warfarin?
MediHelp rates the interaction as major. Voriconazole and Warfarin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Voriconazole increases warfarin exposure, prolonging prothrombin time and raising INR, which increases the risk of bleeding. The effect can appear within days of starting voriconazole and reverses when it is stopped.
How serious is the interaction between Voriconazole and Warfarin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor INR closely when starting or stopping voriconazole, and reduce the warfarin dose as needed. Watch for signs of bleeding.
What other medicines interact with Voriconazole?
MediHelp also lists interactions of Voriconazole with, for example, Avanafil, Butabarbital, Carbamazepine. The full list is on the Voriconazole page.
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