Drug interactions
Darifenacin + Rifampin
Severity: Moderate
Darifenacin and Rifampin: 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
Rifampin strongly induces CYP3A4 and can substantially lower darifenacin exposure. This may lead to loss of efficacy in overactive bladder symptom control.
What this interaction means in plain words
Darifenacin and Rifampin 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
Induction of CYP3A4 (and possibly P-gp) increases the metabolic clearance of darifenacin.
What to do
Monitor for loss of symptom control and consider an alternative therapy or a higher darifenacin dose within the labeled range. Reassess dosing when rifampin is stopped, as enzyme induction wanes over weeks.
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
Frequently asked questions
Can I take Darifenacin with Rifampin?
MediHelp rates the interaction as moderate. Darifenacin and Rifampin 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. Rifampin strongly induces CYP3A4 and can substantially lower darifenacin exposure. This may lead to loss of efficacy in overactive bladder symptom control.
How serious is the interaction between Darifenacin and Rifampin?
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 loss of symptom control and consider an alternative therapy or a higher darifenacin dose within the labeled range. Reassess dosing when rifampin is stopped, as enzyme induction wanes over weeks.
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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