Furosemide and Tamsulosin Interaction
Drug interaction information between Furosemide and Tamsulosin.
Furosemide and Tamsulosin have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Furosemide and Tamsulosin. 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.
How They Interact
Furosemide slightly lowers the level of tamsulosin in your system, but the effect is too small to change how the medicine works.
What To Do
You can take these medicines together safely without changing your dose.
FDA Label Information
7.7 Furosemide Tamsulosin hydrochloride capsules had no effect on the pharmacodynamics (excretion of electrolytes) of furosemide. While furosemide produced an 11% to 12% reduction in tamsulosin hydrochloride C max and AUC, these changes are expected to be clinically insignificant and do not require adjustment of the tamsulosin hydrochloride capsules dosage [see Clinical Pharmacology (12.3)].
Furosemide Also Interacts With
- Dutasteride major
- Dutasteride/Tamsulosin major
- Cyclosporine moderate
- Lithium moderate
- Oxaprozin moderate
Tamsulosin Also Interacts With
- Paroxetine moderate
- Warfarin moderate
- Erythromycin moderate
- Terbinafine moderate
- Dutasteride moderate
Frequently Asked Questions
Can I take Furosemide and Tamsulosin together?
This is a major interaction. You can take these medicines together safely without changing your dose.
How serious is the interaction between Furosemide and Tamsulosin?
This interaction is classified as "major" severity by the FDA. Major interactions may be life-threatening or cause serious side effects.
Why do Furosemide and Tamsulosin interact?
Furosemide slightly lowers the level of tamsulosin in your system, but the effect is too small to change how the medicine works.
Understanding the Furosemide and Tamsulosin Interaction
FDA-approved prescribing information for these two drugs flags their combination as a major-severity interaction. Furosemide belongs to the Loop Diuretic class and Tamsulosin belongs to the Alpha-1 Adrenergic Blocker class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Furosemide slightly lowers the level of tamsulosin in your system, but the effect is too small to change how the medicine works. 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. Furosemide has 36 total documented interactions on file in this dataset, and Tamsulosin has 18. 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: You can take these medicines together safely without changing your 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 Furosemide or Tamsulosin 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.
Read our methodology - how this data is sourced, computed, and verified.