Drug interactions
Cimetidine + Darifenacin
Severity: Moderate
Cimetidine and Darifenacin: 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
Cimetidine raises darifenacin exposure moderately by inhibiting its metabolism, increasing anticholinergic effects such as dry mouth and constipation.
What this interaction means in plain words
Cimetidine and Darifenacin 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.
Cimetidine belongs to Gastrointestinal Tract; Darifenacin belongs to Genitourinary.
Why it happens
Cimetidine inhibits CYP3A4 and CYP2D6 metabolism of darifenacin.
What to do
Limit darifenacin to 7.5 mg daily as labeling advises with moderate CYP3A4 inhibitors, and monitor for anticholinergic effects.
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 Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Other interactions of Darifenacin
Frequently asked questions
Can I take Cimetidine with Darifenacin?
MediHelp rates the interaction as moderate. Cimetidine and Darifenacin 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. Cimetidine raises darifenacin exposure moderately by inhibiting its metabolism, increasing anticholinergic effects such as dry mouth and constipation.
How serious is the interaction between Cimetidine and Darifenacin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit darifenacin to 7.5 mg daily as labeling advises with moderate CYP3A4 inhibitors, and monitor for anticholinergic effects.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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