Drug interactions
Darifenacin + Letermovir
Severity: Moderate
Darifenacin and Letermovir: 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
Letermovir is a moderate CYP3A inhibitor and can increase darifenacin concentrations. This raises the risk of anticholinergic adverse effects.
What this interaction means in plain words
Darifenacin and Letermovir 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; Letermovir belongs to Anti Virals.
Why it happens
Letermovir inhibits CYP3A4, decreasing darifenacin metabolism.
What to do
Monitor for anticholinergic effects and limit darifenacin to 7.5 mg daily during letermovir therapy.
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 Letermovir
- Ergotamine + Letermovir Contraindicated
- Letermovir + Pimozide Contraindicated
- Apalutamide + Letermovir Major
- Atorvastatin + Letermovir Major
- Carbamazepine + Letermovir Major
- Colchicine + Letermovir Major
Frequently asked questions
Can I take Darifenacin with Letermovir?
MediHelp rates the interaction as moderate. Darifenacin and Letermovir 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. Letermovir is a moderate CYP3A inhibitor and can increase darifenacin concentrations. This raises the risk of anticholinergic adverse effects.
How serious is the interaction between Darifenacin and Letermovir?
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 and limit darifenacin to 7.5 mg daily during letermovir therapy.
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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