Drug interactions
Liotrix + Warfarin
Severity: Moderate
Liotrix 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
Liotrix contains levothyroxine and liothyronine, which increase the turnover of vitamin K-dependent clotting factors and strengthen the effect of warfarin. This may cause INR elevation and bleeding.
What this interaction means in plain words
Liotrix 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
Increased catabolism of vitamin K-dependent clotting factors with thyroid hormone replacement.
What to do
Monitor INR frequently when thyroid therapy is started or adjusted, and lower the warfarin dose if the INR rises.
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 Liotrix with Warfarin?
MediHelp rates the interaction as moderate. Liotrix 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. Liotrix contains levothyroxine and liothyronine, which increase the turnover of vitamin K-dependent clotting factors and strengthen the effect of warfarin. This may cause INR elevation and bleeding.
How serious is the interaction between Liotrix 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 frequently when thyroid therapy is started or adjusted, and lower the warfarin dose if the INR rises.
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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