Drug interactions
Darifenacin + Lapatinib
Severity: Moderate
Darifenacin and Lapatinib: 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
Lapatinib is a CYP3A4 substrate and a weak-to-moderate inhibitor of CYP3A4 and CYP2D6 and could raise darifenacin concentrations. The effect is expected to be modest, with more anticholinergic effects.
What this interaction means in plain words
Darifenacin and Lapatinib 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; Lapatinib belongs to Oncology.
Why it happens
Lapatinib inhibits CYP3A4 and CYP2D6, reducing darifenacin clearance.
What to do
Monitor for anticholinergic effects and limit darifenacin to 7.5 mg daily if they occur. Monitor lapatinib tolerability including QT interval.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Darifenacin and Lapatinib, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Darifenacin
Other interactions of Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Frequently asked questions
Can I take Darifenacin with Lapatinib?
MediHelp rates the interaction as moderate. Darifenacin and Lapatinib 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. Lapatinib is a CYP3A4 substrate and a weak-to-moderate inhibitor of CYP3A4 and CYP2D6 and could raise darifenacin concentrations. The effect is expected to be modest, with more anticholinergic effects.
How serious is the interaction between Darifenacin and Lapatinib?
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 if they occur. Monitor lapatinib tolerability including QT interval.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
