Drug interactions
Darifenacin + St john's wort
Severity: Moderate
Darifenacin and St john's wort: 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
St John's wort induces CYP3A4 and P-glycoprotein, which may lower darifenacin concentrations. Reduced bladder symptom control may result.
What this interaction means in plain words
Darifenacin and St john's wort 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.
Why it happens
Induction of CYP3A4 increases the metabolism of darifenacin.
What to do
Advise patients to avoid St John's wort or monitor for reduced efficacy of darifenacin. Re-evaluate response if the herbal product is started or stopped.
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
Frequently asked questions
Can I take Darifenacin with St john's wort?
MediHelp rates the interaction as moderate. Darifenacin and St john's wort 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. St John's wort induces CYP3A4 and P-glycoprotein, which may lower darifenacin concentrations. Reduced bladder symptom control may result.
How serious is the interaction between Darifenacin and St john's wort?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to avoid St John's wort or monitor for reduced efficacy of darifenacin. Re-evaluate response if the herbal product is started or stopped.
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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