Apixaban and Tibolone: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Aug 8, 2026 · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Apixaban
Tibolone
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.
You've been prescribed both apixaban (Eliquis), a blood thinner, and tibolone. Tibolone can boost your body's clot-breaking activity and may make a blood thinner work a little harder than expected. When both are used together, that could raise your chance of bleeding.
I want to be clear: this concern is theoretical, based mostly on studies with a different blood thinner. Watch for things like easy bruising, nosebleeds, bleeding gums, or unusually dark stools. The good news is your care team can manage this easily by keeping an eye on you and adjusting doses if needed. Keep taking both as prescribed and check in with your pharmacist or doctor.
Effect: Potential additive/enhanced anticoagulant effect, increasing bleeding risk.
Mechanism: Tibolone increases blood fibrinolytic activity, which may augment the anticoagulant effect of apixaban (a direct factor Xa inhibitor). Neither drug is a prodrug.
- Direction: Increased anticoagulant/bleeding effect
- Evidence: Theoretical; enhanced anticoagulation demonstrated with warfarin in a randomized crossover study, extrapolated to apixaban
- Onset: Unspecified
- Severity: Moderate
Management: Use caution, particularly when initiating or discontinuing tibolone. Monitor for signs/symptoms of bleeding. Note apixaban lacks a routine coagulation assay; individualize and adjust dosing per clinical judgment if necessary.
What happens
Increased risk of bleeding
Interaction Deep Dive
By increasing fibrinolytic activity in the blood, tibolone can potentiate the action of anticoagulants when the two are taken together. In a double-blind, randomized, placebo-controlled, 2-way crossover study conducted in healthy postmenopausal women, adding tibolone therapy intensified the anticoagulant effect produced by warfarin. Exercise caution when the drugs are given concurrently, particularly at the initiation or discontinuation of tibolone. Adjust the anticoagulant dose if required1.
Why it happens (mechanism)
Increase in blood fibrinolytic activity and enhanced anticoagulant effects
How to manage this interaction
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. This interaction can usually be managed with a little extra attention.
- Be especially watchful when starting or stopping tibolone, since that is when the effect may change.
- Watch for signs of bleeding: easy bruising, nosebleeds, bleeding gums, pink or red urine, or black/tarry stools.
- Your care team may monitor you more closely and, if needed, adjust your blood thinner dose to fit you.
- Tell any provider or dentist that you take both drugs before procedures.
Raise any bleeding concerns with your pharmacist or doctor promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A double-blind, randomized, placebo-controlled, 2-way crossover study found that giving tibolone alongside warfarin increased warfarin-induced anticoagulation in healthy, postmenopausal women. Participants (n=16; aged 50 to 65 years) who were stabilized on oral warfarin (doses of 1 to 8.5 mg) with an INR between 1.4 and 2.0 were randomized to either tibolone 2.5 mg/day for 21 days, then a 7-day washout period, then placebo for 21 days (n=8), or the reverse sequence (n=8). Warfarin was maintained throughout the washout period. In comparison with placebo, tibolone produced a statistically significant rise in the mean INR of 0.4. Among the secondary efficacy measures, coagulation factors II, VII, VIIa, and X were each statistically significantly reduced during tibolone treatment relative to placebo. The estimated mean difference came to -6.9% for Factor VIIa and -31% for Factor VII. Significant differences between individuals were observed in the INR and coagulation factor responses across the 2 treatment periods. Overall, all treatments were well tolerated, with no clinically significant adverse events. Although the precise mechanism of this interaction was not clear, competition for protein binding sites or pharmacodynamic factors were suggested as possible mechanisms 2.
Common questions
Can I take Apixaban and Tibolone together?
Tibolone may enhance apixaban's blood-thinning effect and slightly raise bleeding risk, mainly a theoretical concern. Keep taking both, watch for bleeding, and let your care team monitor you, especially when tibolone is started or stopped. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Apixaban and Tibolone 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 is the Apixaban and Tibolone interaction managed?
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. This interaction can usually be managed with a little extra attention. Be especially watchful when starting or stopping tibolone, since that is when the effect may change. Watch for signs of bleeding: easy bruising, nosebleeds, bleeding gums, pink or red urine, or black/tarry stools. Your care team may monitor you… Management is individual — always follow your own care team's guidance.
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 Apixaban or Tibolone 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 (2)
- Product Information: Livial oral tablets, tibolone oral tablets. Merck Sharp & Dohme Limited (per eMC+), Hoddesdon, United Kingdom, 2015.
- Elbers J, Hageluken C, & Wadham A: Tibolone (Livial(R)) enhances warfarin-induced anticoagulation in postmenopausal women. Maturitas 2007; 56(1):94-100.
Keep reading about Apixaban
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