Drug interactions
Darifenacin + Fesoterodine
Severity: Moderate
Darifenacin and Fesoterodine: 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
Both drugs are antimuscarinic agents for overactive bladder, so combining them duplicates therapy and increases anticholinergic adverse effects such as dry mouth, constipation, urinary retention, blurred vision and cognitive impairment. There is no established benefit from the combination.
What this interaction means in plain words
Darifenacin and Fesoterodine 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; Fesoterodine belongs to Genitourinary.
Why it happens
Additive pharmacodynamic antagonism at muscarinic receptors.
What to do
Avoid combining two antimuscarinic bladder agents; optimise the dose of a single drug or switch class (e.g. a beta-3 agonist).
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?
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Other interactions of Darifenacin
Other interactions of Fesoterodine
Frequently asked questions
Can I take Darifenacin with Fesoterodine?
MediHelp rates the interaction as moderate. Darifenacin and Fesoterodine 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. Both drugs are antimuscarinic agents for overactive bladder, so combining them duplicates therapy and increases anticholinergic adverse effects such as dry mouth, constipation, urinary retention, blurred vision and cognitive impairment. There is no established benefit from the combination.
How serious is the interaction between Darifenacin and Fesoterodine?
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 combining two antimuscarinic bladder agents; optimise the dose of a single drug or switch class (e.g. a beta-3 agonist).
What other medicines interact with Darifenacin?
MediHelp also lists interactions of Darifenacin with, for example, Atazanavir, Bethanechol, Clarithromycin. The full list is on the Darifenacin page.
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