Dutasteride/Tamsulosin and Ketoconazole Interaction
Drug interaction information between Dutasteride/Tamsulosin and Ketoconazole.
Dutasteride/Tamsulosin and Ketoconazole have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Dutasteride/Tamsulosin and Ketoconazole. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Ketoconazole stops the body from breaking down tamsulosin, which can cause the drug to build up to unsafe levels.
FDA Label Information
Concomitant treatment with ketoconazole (a strong inhibitor of CYP3A4) resulted in increases in the C max and AUC of tamsulosin by factors of 2.2 and 2.8, respectively. Since CYP2D6 PMs cannot be readily identified and the potential for significant increase in tamsulosin exposure exists when tamsulosin 0.4 mg is coadministered with strong CYP3A4 inhibitors in CYP2D6 PMs, tamsulosin 0.4 mg capsules should not be used in combination with strong inhibitors of CYP3A4 (e.g., ketoconazole).
Dutasteride/Tamsulosin Also Interacts With
- Furosemide major
- Tamsulosin moderate
- Warfarin moderate
- Paroxetine minor
- Atenolol minor
Ketoconazole Also Interacts With
- Alfuzosin major
- Dronedarone major
- Ranolazine major
- Saxagliptin major
- Sildenafil major
Frequently Asked Questions
What SPL severity band is on file for Dutasteride/Tamsulosin + Ketoconazole?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Ketoconazole has 113 labeled pairs on file vs Dutasteride/Tamsulosin's 15. In the minor band specifically: Dutasteride/Tamsulosin has 12 (also Paroxetine, Atenolol, Diltiazem, Nifedipine); Ketoconazole has 85 (also Abiraterone, Acetaminophen/Oxycodone, Alosetron, Amphotericin B).
What mechanism field is on file for Dutasteride/Tamsulosin and Ketoconazole?
Ketoconazole stops the body from breaking down tamsulosin, which can cause the drug to build up to unsafe levels.
Ketoconazole carries more major-labeled pairs than Dutasteride/Tamsulosin
SPL source-record counts only. This page's band is minor · classes on file: Dutasteride/Tamsulosin (5-ARI / Alpha-Blocker Combination); Ketoconazole (Azole Antifungal).
Ketoconazole has 6 major-labeled pairs vs Dutasteride/Tamsulosin's 1. This page itself is in the minor band, not the major band.
1 major · 2 moderate · 12 minor · 15 total
- Other minor peers for Dutasteride/Tamsulosin
- Paroxetine
- Atenolol
- Diltiazem
- Nifedipine
6 major · 22 moderate · 85 minor · 113 total
- Other minor peers for Ketoconazole
- Abiraterone
- Acetaminophen/Oxycodone
- Alosetron
- Amphotericin B
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.