Drug interactions
Darifenacin + Fosaprepitant
Severity: Moderate
Darifenacin and Fosaprepitant: 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
Fosaprepitant is converted to aprepitant, a moderate CYP3A4 inhibitor that may briefly raise darifenacin exposure. Effects are typically short-lived after a single dose.
What this interaction means in plain words
Darifenacin and Fosaprepitant 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; Fosaprepitant belongs to Gastrointestinal Tract.
Why it happens
Aprepitant inhibits CYP3A4, reducing darifenacin metabolism.
What to do
Monitor for anticholinergic effects for several days after the dose; reduce the darifenacin dose if symptoms occur.
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 Fosaprepitant
- Flibanserin + Fosaprepitant Contraindicated
- Fosaprepitant + Pimozide Contraindicated
- Alprazolam + Fosaprepitant Moderate
- Amiodarone + Fosaprepitant Moderate
- Amobarbital + Fosaprepitant Moderate
- Apalutamide + Fosaprepitant Moderate
Frequently asked questions
Can I take Darifenacin with Fosaprepitant?
MediHelp rates the interaction as moderate. Darifenacin and Fosaprepitant 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. Fosaprepitant is converted to aprepitant, a moderate CYP3A4 inhibitor that may briefly raise darifenacin exposure. Effects are typically short-lived after a single dose.
How serious is the interaction between Darifenacin and Fosaprepitant?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for anticholinergic effects for several days after the dose; reduce the darifenacin dose if symptoms occur.
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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