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Darifenacin and Thioridazine Interaction

Drug interaction information between Darifenacin and Thioridazine.

Darifenacin and Thioridazine have a documented moderate interaction in FDA labeling.

FDA drug labeling documents a moderate-severity interaction between Darifenacin and Thioridazine. 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

Thioridazine

Typical Antipsychotic (Phenothiazine)

How They Interact

Darifenacin can slow down the way your body breaks down thioridazine. This can cause thioridazine to build up to unsafe levels in your blood, which may lead to dangerous side effects.

What To Do

Use this combination with caution. Your doctor may need to adjust your dosage or monitor you more frequently for side effects.

FDA Label Information

7 DRUG INTERACTIONS Caution should be taken when darifenacin extended-release tablets are used concomitantly with medications that are predominantly metabolized by CYP2D6 and which have a narrow therapeutic window, such as flecainide, thioridazine and tricyclic antidepressants ( 7.2 ) The concomitant use of darifenacin extended-release tablets with other anticholinergic agents may increase the frequency and/or severity of dry mouth, constipation, blurred vision and other anticholinergic pharmacological effects. 7.3 CYP2D6 Substrates Caution should be taken when darifenacin extended-release...

Frequently Asked Questions

Can I take Darifenacin and Thioridazine together?

This is a moderate interaction. Use this combination with caution. Your doctor may need to adjust your dosage or monitor you more frequently for side effects.

How serious is the interaction between Darifenacin and Thioridazine?

This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.

Why do Darifenacin and Thioridazine interact?

Darifenacin can slow down the way your body breaks down thioridazine. This can cause thioridazine to build up to unsafe levels in your blood, which may lead to dangerous side effects.

Understanding the Darifenacin and Thioridazine Interaction

FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Darifenacin belongs to the Anticholinergic (Overactive Bladder) class and Thioridazine belongs to the Typical Antipsychotic (Phenothiazine) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Darifenacin can slow down the way your body breaks down thioridazine. 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 Thioridazine has 17. 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: Use this combination with caution. 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 Thioridazine 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.