Drug interactions
Amitriptyline + Darifenacin
Severity: Moderate
Amitriptyline 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
Amitriptyline is strongly anticholinergic and combined with darifenacin the antimuscarinic burden rises, causing dry mouth, constipation, urinary retention, blurred vision and cognitive impairment. Darifenacin inhibits CYP2D6, which may also modestly raise tricyclic concentrations.
What this interaction means in plain words
Amitriptyline 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.
Amitriptyline belongs to Central Nervous System; Darifenacin belongs to Genitourinary.
Why it happens
Additive antimuscarinic effects plus CYP2D6 inhibition by darifenacin reducing tricyclic metabolism.
What to do
Monitor for anticholinergic toxicity and tricyclic adverse effects, and lower the amitriptyline dose if needed. Avoid in elderly patients with cognitive impairment.
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 Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Darifenacin?
MediHelp rates the interaction as moderate. Amitriptyline 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. Amitriptyline is strongly anticholinergic and combined with darifenacin the antimuscarinic burden rises, causing dry mouth, constipation, urinary retention, blurred vision and cognitive impairment. Darifenacin inhibits CYP2D6, which may also modestly raise tricyclic concentrations.
How serious is the interaction between Amitriptyline 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: Monitor for anticholinergic toxicity and tricyclic adverse effects, and lower the amitriptyline dose if needed. Avoid in elderly patients with cognitive impairment.
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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