Drug interactions
Darifenacin + Doxepin
Severity: Moderate
Darifenacin and Doxepin: 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
Both drugs have anticholinergic effects, so combined use raises the risk of dry mouth, constipation, urinary retention and confusion. Darifenacin may also modestly raise doxepin levels, which are partly cleared by CYP2D6.
What this interaction means in plain words
Darifenacin and Doxepin 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; Doxepin belongs to Dermatology.
Why it happens
Additive antimuscarinic effects plus weak CYP2D6 inhibition by darifenacin.
What to do
Monitor for anticholinergic effects, especially in older adults, and lower the doxepin dose if needed.
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 Doxepin
- Doxepin + Isocarboxazid Contraindicated
- Doxepin + Phenelzine Contraindicated
- Doxepin + Procarbazine Contraindicated
- Doxepin + Safinamide Contraindicated
- Doxepin + Selegiline Contraindicated
- Doxepin + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Darifenacin with Doxepin?
MediHelp rates the interaction as moderate. Darifenacin and Doxepin 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. Both drugs have anticholinergic effects, so combined use raises the risk of dry mouth, constipation, urinary retention and confusion. Darifenacin may also modestly raise doxepin levels, which are partly cleared by CYP2D6.
How serious is the interaction between Darifenacin and Doxepin?
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, especially in older adults, and lower the doxepin dose if needed.
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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