Drug Interaction Report

Anisindione and Fluoxymesterone: Interaction Details

A pharmacist-reviewed analysis of the Anisindione and Fluoxymesterone 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

Fluoxymesterone

Android-F® Androxy® Halotestin® Ora-Testryl®
+

Anisindione

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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 43 documented Anisindione interactions, 5 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
delayed
Evidence
theoretical
Severity
Major

What happens

Increased risk of bleeding

Interaction Deep Dive

A number of case reports have demonstrated that coadministration of oral anticoagulants and 17-alkylated androgens (fluoxymesterone, oxandrolone, oxymetholone, methyltestosterone, methandrostenolone, stanozolol) has resulted in a prolonged prothrombin time and hemorrhages12345.

Why it happens (mechanism)

Unknown

Literature reports

2 reports — tap to read

a) Anabolic steroids have been well documented to cause important interactions with dicumarol. The anabolic steroids enhance dicumarol's anticoagulant activity perhaps through reductions in clotting factor formation and increased clotting factor degradation. The 17-alpha-alkylated steroids (fluoxymesterone, oxandrolone, oxymetholone, methyltestosterone, methandrostenolone, stanozolol) appear to be more likely to induce this reaction than the non-substituted steroids 12345.

b) Fluoxymesterone may suppress clotting factors II, V, VII, and X; therefore bleeding may occur in those on concomitant anticoagulant drugs 6.

Common questions

Can I take Anisindione and Fluoxymesterone together?

Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.

How serious is the Anisindione and Fluoxymesterone 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Anisindione or Fluoxymesterone 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 (6)

  1. Schrogie JJ & Solomon HM: The anticoagulant response to bishydroxycoumarin. II. The effect of D-thyroxine, clofibrate, and norethandrolone. Clin Pharmacol Ther 1967; 8:70-77. PubMed
  2. Lorentz SM & Weibert RT: Potentiation of warfarin anticoagulation by topical testosterone ointment. Clin Pharm 1985; 4:332-334.
  3. Robinson BH, Hawkins JB, Ellis JE, et al: Decreased anticoagulant tolerance with oxymetholone. Lancet 1971; 1:1356. DOI
  4. Longridge RG, Gillam PM, & Barton GM: Decreased anticoagulant tolerance with oxymetholone. Lancet 1971; 2:90. PubMed
  5. Edwards MS & Curtis JR: Decreased anticoagulant tolerance with oxymetholone. Lancet 1971; 2:221. DOI
  6. Product Information: Halotestin(R), fluoxymesterone. Upjohn Company, Kalamazoo, MI, 1995. DailyMed
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Fluoxymesterone

Keep reading about Fluoxymesterone

All Fluoxymesterone interactions (8) Fluoxymesterone drug information
Also serious with: Dicumarol Phenprocoumon
Anisindione

Keep reading about Anisindione

All Anisindione interactions (43)
Also serious with: Aspirin Aspirin Rectal Danazol Oxandrolone
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:

Fluoxymesterone + Activated Charcoal Coffee Charcoal European Mandrake Glucomannan Guar Gum Gum Arabic Slippery Elm Tragacanth + 9 more
Anisindione + 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.

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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.