Levothyroxine and Dabigatran Etexilate: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Levothyroxine
Dabigatran Etexilate
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased response to oral anticoagulant therapy
Interaction Deep Dive
Concomitant use of levothyroxine and oral anticoagulants increases the response to oral anticoagulant therapy. Therefore, a decrease in the dose of anticoagulant may be warranted with correction of the hypothyroid state or when the levothyroxine dose is increased. Closely monitor prothrombin time2 or other coagulation tests to allow for appropriate and timely dosage adjustments 31.
Why it happens (mechanism)
An unknown mechanism
Common questions
Can I take Levothyroxine and Dabigatran Etexilate together?
Increased response to oral anticoagulant therapy Always confirm with your pharmacist or prescriber before making any change.
How serious is the Levothyroxine and Dabigatran Etexilate interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Levothyroxine or Dabigatran Etexilate need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (3)
- Product Information: TIROSINT(R)-SOL oral solution, levothyroxine sodium oral solution. IBSA Pharma Inc. (per FDA), Parsippany, NJ, 2023. DailyMed
- Product Information: levothyroxine sodium injection powder for solution, levothyroxine sodium injection powder for solution. Fresenius Kabi USA, LLC, Lake Zurich, IL, 2017. DailyMed
- Product Information: SYNTHROID(R) oral tablets, levothyroxine sodium oral tablets. AbbVie Inc (per FDA), North Chicago, IL, 2024. DailyMed
Keep reading about Levothyroxine
Keep reading about Dabigatran Etexilate
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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