Drug interactions
Peginterferon alfa 2a + Warfarin
Severity: Moderate
Peginterferon alfa 2a and Warfarin: moderate 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
Interferon therapy has been associated with increased anticoagulant effect and INR changes in patients taking warfarin. Interferons can also cause thrombocytopenia and liver dysfunction, which add to bleeding risk.
What this interaction means in plain words
Peginterferon alfa 2a and Warfarin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Peginterferon alfa 2a belongs to Anti Virals; Warfarin belongs to Cardiovascular.
Why it happens
Probably altered warfarin metabolism and hepatic function, plus interferon-induced thrombocytopenia; the exact mechanism is not established.
What to do
Check INR more often when starting, changing or stopping peginterferon. Adjust the warfarin dose by INR and monitor platelet counts.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Peginterferon alfa 2a
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 Peginterferon alfa 2a with Warfarin?
MediHelp rates the interaction as moderate. Peginterferon alfa 2a and Warfarin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Interferon therapy has been associated with increased anticoagulant effect and INR changes in patients taking warfarin. Interferons can also cause thrombocytopenia and liver dysfunction, which add to bleeding risk.
How serious is the interaction between Peginterferon alfa 2a and Warfarin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check INR more often when starting, changing or stopping peginterferon. Adjust the warfarin dose by INR and monitor platelet counts.
What other medicines interact with Peginterferon alfa 2a?
MediHelp also lists interactions of Peginterferon alfa 2a with, for example, Clozapine, Deferiprone, Hydroxyurea. The full list is on the Peginterferon alfa 2a page.
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