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Darifenacin and Duloxetine Interaction

Drug interaction information between Darifenacin and Duloxetine.

Darifenacin and Duloxetine have a documented minor interaction in FDA labeling.

FDA drug labeling documents a minor-severity interaction between Darifenacin and Duloxetine. 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

Darifenacin

Anticholinergic (Overactive Bladder)

Drug B

Duloxetine

Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)

How They Interact

Duloxetine blocks a specific liver protein that helps clear darifenacin from the body. This can lead to slightly higher levels of darifenacin.

What To Do

You can safely take these medications together without adjusting your dosage.

FDA Label Information

7.2 CYP2D6 Inhibitors No dosing adjustments are recommended in the presence of CYP2D6 inhibitors (for example, paroxetine, fluoxetine, quinidine and duloxetine) [see Clinical Pharmacology (12.3) ] .

Frequently Asked Questions

Can I take Darifenacin and Duloxetine together?

This is a minor interaction. You can safely take these medications together without adjusting your dosage.

How serious is the interaction between Darifenacin and Duloxetine?

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 Darifenacin and Duloxetine interact?

Duloxetine blocks a specific liver protein that helps clear darifenacin from the body. This can lead to slightly higher levels of darifenacin.

Understanding the Darifenacin and Duloxetine Interaction

FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Darifenacin belongs to the Anticholinergic (Overactive Bladder) class and Duloxetine belongs to the Serotonin-Norepinephrine Reuptake Inhibitor (SNRI) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Duloxetine blocks a specific liver protein that helps clear darifenacin from the body. 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. Darifenacin has 18 total documented interactions on file in this dataset, and Duloxetine 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 safely take these medications together without adjusting your dosage. 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 Darifenacin or Duloxetine 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.