Drug interactions
Doxepin + Tolterodine
Severity: Moderate
Doxepin and Tolterodine: 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 is a tricyclic antidepressant with anticholinergic and sedative effects, and combining it with tolterodine may increase dry mouth, constipation, urinary retention, confusion and tachycardia. Both drugs may also affect the QT interval.
What this interaction means in plain words
Doxepin and Tolterodine 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; Tolterodine belongs to Genitourinary.
Why it happens
Additive muscarinic receptor blockade, with possible additive QT effects.
What to do
Monitor for urinary retention, constipation, sedation and cognitive changes, especially in older adults. Use the lowest effective doses or a less anticholinergic alternative.
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 Tolterodine
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 Tolterodine?
MediHelp rates the interaction as moderate. Doxepin and Tolterodine 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 is a tricyclic antidepressant with anticholinergic and sedative effects, and combining it with tolterodine may increase dry mouth, constipation, urinary retention, confusion and tachycardia. Both drugs may also affect the QT interval.
How serious is the interaction between Doxepin and Tolterodine?
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 urinary retention, constipation, sedation and cognitive changes, especially in older adults. Use the lowest effective doses or a less anticholinergic alternative.
What other medicines interact with Tolterodine?
MediHelp also lists interactions of Tolterodine with, for example, Clarithromycin, Clozapine, Cobicistat. The full list is on the Tolterodine page.
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