Drug Interaction Report

Phenprocoumon and Disulfiram: Interaction Details

Name: Phenprocoumon and Disulfiram Interaction
Creator: Dr. Brian Staiger, PharmD, BCPS

A pharmacist-reviewed analysis of the Phenprocoumon and Disulfiram 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

Disulfiram

Antabuse Antabuse®

Phenprocoumon

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 97 documented Phenprocoumon interactions, 25 are rated moderate — including this one.

Onset

delayed

Evidence

probable

Severity

Moderate

What happens

Increased risk of bleeding

Interaction Deep Dive

Disulfiram has been shown to increase the hypoprothrombinemic effect of warfarin¹²³⁴ and a similar reaction with other coumarins is expected.

Why it happens (mechanism)

Decreased phenprocoumon metabolism

Common questions

Can I take Phenprocoumon and Disulfiram together?

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

How serious is the Phenprocoumon and Disulfiram 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 "probable". Good supporting evidence, though not definitively proven.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Cough Medicines Safe To Take With Disulfiram

Questions for your pharmacist

Does my dose of Phenprocoumon or Disulfiram 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 (4)

O'Reilly RA: Interaction of sodium warfarin and disulfiram (Antabuse) in man. Ann Intern Med 1973; 78:73. PubMed
Rothstein E: Warfarin effect enhanced by disulfiram (letter). JAMA 1968; 206:1574-1575. PubMed
Rothstein E: Warfarin effect enhanced by disulfiram (Antabuse) (letter). JAMA 1972; 221:1052-1053. PubMed
O'Reilly RA: Potentiation of anticoagulant effect by disulfiram. Clin Res 1971; 19:180.

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Disulfiram

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All Disulfiram interactions (45) Disulfiram drug information

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Phenprocoumon

Keep reading about Phenprocoumon

All Phenprocoumon interactions (97)

Also serious with: Defibrotide Injection Etodolac Nintedanib 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:

Disulfiram + Activated Charcoal Bach Flower Remedies Beer Wine Biofeedback Black Tea Caffeine Cannabinol (cbn) + 37 more

Phenprocoumon + Activated Charcoal Danshen Piracetam St. John's Wort Aconite Allspice Aloe Alpha-lipoic Acid + 211 more

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

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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.