Does Tamsulosin Interact With Warfarin?

(5.2, 7.1, 12.3) Should not be used in combination with other alpha adrenergic blocking agents (5.2, 7.2, 12.3) Exercise caution with concomitant administration of warfarin (5.2, 7.4, 12.3) Advise patients about the possibility and seriousness of priapism (5.3) Intraoperative Floppy Iris Syndrome has been observed during cataract and glaucoma surgery in some patients.

Severity: Major

Severity basis: warnings section (keywords: should not be used). Combining Tamsulosin (Alpha-1 blocker (BPH)) and Warfarin (Vitamin K antagonist anticoagulant) is classified as a major interaction.

What to Do

The label advises avoiding this combination or using it only under close medical supervision. Talk to your prescriber or pharmacist before combining them.

From the FDA Label

(5.2, 7.1, 12.3) Should not be used in combination with other alpha adrenergic blocking agents (5.2, 7.2, 12.3) Exercise caution with concomitant administration of warfarin (5.2, 7.4, 12.3) Advise patients about the possibility and seriousness of priapism (5.3) Intraoperative Floppy Iris Syndrome has been observed during cataract and glaucoma surgery in some patients.

Source: FDA structured product labeling (set_id 00097e78-9c04-4e62-8260-ddb50e9a6a93).

Tamsulosin

Alpha-1 blocker (BPH)

Brands: Flomax

View Tamsulosin safety profile

Warfarin

Vitamin K antagonist anticoagulant

Brands: Coumadin, Jantoven

View Warfarin safety profile

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This information is educational — not medical advice.

This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.

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