Drug interactions
Doxepin + Fesoterodine
Severity: Moderate
Doxepin and Fesoterodine: 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
Doxepin has strong anticholinergic properties that add to those of fesoterodine. This raises the risk of dry mouth, constipation, urinary retention, blurred vision, confusion and tachycardia, particularly in older adults.
What this interaction means in plain words
Doxepin and Fesoterodine 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.
Doxepin belongs to Dermatology; Fesoterodine belongs to Genitourinary.
Why it happens
Additive muscarinic receptor blockade.
What to do
Monitor for anticholinergic toxicity, especially in older patients, and use the lowest effective doses or choose a less anticholinergic antidepressant.
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 Fesoterodine
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 Doxepin with Fesoterodine?
MediHelp rates the interaction as moderate. Doxepin and Fesoterodine 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. Doxepin has strong anticholinergic properties that add to those of fesoterodine. This raises the risk of dry mouth, constipation, urinary retention, blurred vision, confusion and tachycardia, particularly in older adults.
How serious is the interaction between Doxepin and Fesoterodine?
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, especially in older patients, and use the lowest effective doses or choose a less anticholinergic antidepressant.
What other medicines interact with Fesoterodine?
MediHelp also lists interactions of Fesoterodine with, for example, Bethanechol, Clozapine, Levoketoconazole. The full list is on the Fesoterodine page.
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