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Drug interactions

Darifenacin + Flavoxate

Severity: Moderate

Darifenacin and Flavoxate: moderate interaction.

Last updated

For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.

Summary

Darifenacin is a selective M3 antimuscarinic, so adding flavoxate duplicates antimuscarinic therapy for the bladder. This increases dry mouth, constipation, urinary retention and blurred vision with little added benefit.

What this interaction means in plain words

Darifenacin and Flavoxate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.

Darifenacin belongs to Genitourinary; Flavoxate belongs to Genitourinary.

Evidence level: Moderate

Why it happens

Additive antimuscarinic pharmacodynamic effects.

What to do

Avoid routine duplication of bladder antimuscarinics. If combined, monitor post-void residual and constipation.

What to ask your pharmacist

  • Should I take them at different times of day?
  • Does the dose of either medicine need to change?
  • Is there anything I should avoid, such as alcohol or certain foods, while on both?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Darifenacin with Flavoxate?

MediHelp rates the interaction as moderate. Darifenacin and Flavoxate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Darifenacin is a selective M3 antimuscarinic, so adding flavoxate duplicates antimuscarinic therapy for the bladder. This increases dry mouth, constipation, urinary retention and blurred vision with little added benefit.

How serious is the interaction between Darifenacin and Flavoxate?

MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid routine duplication of bladder antimuscarinics. If combined, monitor post-void residual and constipation.

What other medicines interact with Flavoxate?

MediHelp also lists interactions of Flavoxate with, for example, Clozapine, Abobotulinumtoxina, Aclidinium. The full list is on the Flavoxate page.

Full monographs, dosing and an interaction checker in the MediHelp app

Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.

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