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Dutasteride/Tamsulosin and Diltiazem Interaction

Drug interaction information between Dutasteride/Tamsulosin and Diltiazem.

Dutasteride/Tamsulosin and Diltiazem have a documented minor interaction in FDA labeling.

FDA drug labeling documents a minor-severity interaction between Dutasteride/Tamsulosin and Diltiazem. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.

Drug A

Dutasteride/Tamsulosin

5-ARI / Alpha-Blocker Combination

Drug B

Diltiazem

Calcium Channel Blocker

How They Interact

Diltiazem slows down how the body removes dutasteride, which can lead to higher levels of the drug in your blood.

What To Do

Your doctor may need to monitor you more closely for side effects or adjust your medication dose.

FDA Label Information

7.6 Calcium Channel Antagonists Dutasteride Coadministration of verapamil or diltiazem decreases dutasteride clearance and leads to increased exposure to dutasteride.

Dutasteride/Tamsulosin Also Interacts With

View all Dutasteride/Tamsulosin interactions →

Frequently Asked Questions

Can I take Dutasteride/Tamsulosin and Diltiazem together?

This is a minor interaction. Your doctor may need to monitor you more closely for side effects or adjust your medication dose.

How serious is the interaction between Dutasteride/Tamsulosin and Diltiazem?

This interaction is classified as "minor" severity by the FDA. Minor interactions are unlikely to cause significant problems but should still be mentioned to your healthcare provider.

Why do Dutasteride/Tamsulosin and Diltiazem interact?

Diltiazem slows down how the body removes dutasteride, which can lead to higher levels of the drug in your blood.

Understanding the Dutasteride/Tamsulosin and Diltiazem Interaction

FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Dutasteride/Tamsulosin belongs to the 5-ARI / Alpha-Blocker Combination class and Diltiazem belongs to the Calcium Channel Blocker class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Diltiazem slows down how the body removes dutasteride, which can lead to higher levels of the drug in your blood. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.

Context around a specific patient determines real-world impact. Dutasteride/Tamsulosin has 15 total documented interactions on file in this dataset, and Diltiazem has 46. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Your doctor may need to monitor you more closely for side effects or adjust your medication dose. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.

An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Dutasteride/Tamsulosin or Diltiazem based on a web page, speak with your prescriber or pharmacist before making any change.

Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.