Drug interactions
Fesoterodine + St john's wort
Severity: Moderate
Fesoterodine 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 may reduce exposure to fesoterodine's active metabolite. This could weaken control of overactive bladder symptoms.
What this interaction means in plain words
Fesoterodine 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
CYP3A4 induction increases clearance of the active metabolite of fesoterodine.
What to do
Advise patients to avoid St John's wort or monitor for loss of efficacy. Reassess response when 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 Fesoterodine
Frequently asked questions
Can I take Fesoterodine with St john's wort?
MediHelp rates the interaction as moderate. Fesoterodine 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 may reduce exposure to fesoterodine's active metabolite. This could weaken control of overactive bladder symptoms.
How serious is the interaction between Fesoterodine 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 loss of efficacy. Reassess response when the herbal product is started or stopped.
What other medicines interact with Fesoterodine?
MediHelp also lists interactions of Fesoterodine with, for example, Bethanechol, Clozapine, Levoketoconazole. The full list is on the Fesoterodine page.
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