Bicalutamide and Acenocoumarol: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acenocoumarol
No brand names on recordBicalutamide
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
An increased risk of bleeding
Interaction Deep Dive
Concomitant use of bicalutamide and coumarin anticoagulants may result in the displacement of coumarin anticoagulants from protein-binding sites and increase the risk of bleeding. There have been reports of patients stabilized with coumarin anticoagulants who have experienced excessive prolongation of prothrombin time and INR occurring days to week following initiation of bicalutamide. These cases have included hemorrhage and serious intracranial, retroperitoneal, and gastrointestinal bleeding requiring blood transfusion and/or the administration of vitamin K. If coadministered, closely monitor prothrombin and INR, and adjust the anticoagulant dosage as needed1.
Why it happens (mechanism)
Displacement of coumarin anticoagulants from protein-binding sites by bicalutamide
Literature reports
1 report — tap to read
a) There have been reports of patients stabilized with coumarin anticoagulants who have experienced excessive prolongation of prothrombin time and INR occurring days to week following initiation of bicalutamide. These cases have included hemorrhage and serious intracranial, retroperitoneal, and gastrointestinal bleeding requiring blood transfusion and/or the administration of vitamin K 1.
Common questions
Can I take Bicalutamide and Acenocoumarol together?
An increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.
How serious is the Bicalutamide and Acenocoumarol interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Bicalutamide or Acenocoumarol 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 a safer alternative to one of these medications for me?
References (1)
- Product Information: CASODEX(R) oral tablets, bicalutamide oral tablets. AstraZeneca Pharmaceuticals LP (per FDA), Wilmington, DE, 2017. DailyMed
Keep reading about Acenocoumarol
Keep reading about Bicalutamide
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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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