Drug interactions
Thyroid desiccated + Warfarin
Severity: Moderate
Thyroid desiccated 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
Thyroid hormone increases catabolism of vitamin K-dependent clotting factors, which strengthens warfarin's effect. The INR can rise after thyroid replacement is started or its dose increased, with a risk of bleeding.
What this interaction means in plain words
Thyroid desiccated 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.
Why it happens
Thyroid hormone increases the degradation rate of vitamin K-dependent clotting factors, enhancing the pharmacodynamic effect of warfarin.
What to do
Monitor INR closely when starting, stopping or adjusting thyroid doses and reduce the warfarin dose if needed.
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 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 Thyroid desiccated with Warfarin?
MediHelp rates the interaction as moderate. Thyroid desiccated 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. Thyroid hormone increases catabolism of vitamin K-dependent clotting factors, which strengthens warfarin's effect. The INR can rise after thyroid replacement is started or its dose increased, with a risk of bleeding.
How serious is the interaction between Thyroid desiccated 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: Monitor INR closely when starting, stopping or adjusting thyroid doses and reduce the warfarin dose if needed.
What other medicines interact with Warfarin?
MediHelp also lists interactions of Warfarin with, for example, Defibrotide, Ketorolac, Abciximab. The full list is on the Warfarin page.
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