Drug Interaction Report

Dicumarol and Estradiol: Interaction Details

Name: Dicumarol and Estradiol Interaction
Creator: Dr. Brian Staiger, PharmD, BCPS

A pharmacist-reviewed analysis of the Dicumarol and Estradiol interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Estradiol

Delestrogen

Dicumarol

No brand names on record

Medically reviewed by

Dr. Brian Staiger, PharmD, BCPS

Updated Aug 8, 2026

Editorial policy · Data sources

Interaction severity

Moderate

Can be significant — usually manageable with monitoring.

Minor

Moderate

Major

Contraindicated

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.

Of 61 documented Dicumarol interactions, 54 are rated moderate — including this one.

Onset

delayed

Evidence

theoretical

Severity

Moderate

What happens

Decreased anticoagulant effectiveness

Interaction Deep Dive

Concomitant combination contraceptive and dicumarol therapy may result in diminished or enhanced dicumarol activity. Combination contraceptives may increase Factor VII, IX, X and XII while decreasing Factor III¹².

Why it happens (mechanism)

Unknown

Common questions

Can I take Dicumarol and Estradiol together?

Decreased anticoagulant effectiveness Always confirm with your pharmacist or prescriber before making any change.

How serious is the Dicumarol and Estradiol interaction?

It is rated moderate. Can be significant — usually manageable with 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 "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:

Does Saw Palmetto Interact With Estradiol?

Questions for your pharmacist

Does my dose of Dicumarol or Estradiol 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)

Schrogie JJ, Solomon HM, & Zieve PD: Effect of oral contraceptives on vitamin K-dependent clotting activity. Clin Pharmacol Ther 1967; 8:670-675.
de Teresa E, Vera A, Ortigosa J, et al: Interaction between anticoagulants and contraceptives: an unexpected finding. Br Med J 1979; 2:1260-1261.

Was this write-up helpful?

Estradiol

Keep reading about Estradiol

All Estradiol interactions (216) Estradiol drug information

Also serious with: Ensitrelvir Tranexamic Acid Fezolinetant Penicillin V Potassium

Dicumarol

Keep reading about Dicumarol

All Dicumarol interactions (61)

Also serious with: Amoxicillin Aspirin Oxandrolone Danazol

Beyond drug–drug

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:

Estradiol + Activated Charcoal Grapefruit St. John's Wort Acacia Rigidula Adrafinil African Wild Potato Aletris Alfalfa + 205 more

Dicumarol + Activated Charcoal Danshen Piracetam Aconite Allspice Aloe Alpha-lipoic Acid Andrographis + 210 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

Check another combination

Our instant two-drug interaction checker is almost here.

Coming soon

The instant two-drug checker is on its way.

In the meantime, browse the directory below to look up any drug and see its documented interactions.

Still have questions about this combination?

Every question gets a real answer from a licensed pharmacist — free, and usually within a day.

Ask the pharmacist

A message from HelloPharmacist

About our interaction database: depth, not breadth

HelloPharmacist doesn't license one of the big commercial interaction databases, so what you'll find here is not a complete list of every known drug interaction. Instead, each entry is researched, analyzed, and written up individually — documented from the published literature, reviewed by a pharmacist, and cited so you can check every source yourself.

If a combination isn't listed here, it means we haven't documented it yet — never that it's safe. For screening a full medication list, we recommend pairing this site with a comprehensive tool like the Drugs.com Interaction Checker and, most importantly, a review by your own pharmacist. For a deep, plain-English, fully sourced explanation of a specific documented interaction — that's exactly what we built this for.

This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.