Drug interactions
Doxepin + Doxylamine
Severity: Moderate
Doxepin and Doxylamine: 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 strong antihistaminic and anticholinergic activity, and doxylamine adds more of both. Together they can cause marked sedation, confusion, dry mouth, urinary retention and constipation. Older patients are particularly vulnerable.
What this interaction means in plain words
Doxepin and Doxylamine 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; Doxylamine belongs to Respiratory.
Why it happens
Additive H1-antihistamine, sedative and anticholinergic effects.
What to do
Avoid routine co-use of doxylamine with antidepressant-dose doxepin, especially in older adults. Monitor for sedation and anticholinergic toxicity and reduce doses if they occur.
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 Doxylamine
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 Doxylamine?
MediHelp rates the interaction as moderate. Doxepin and Doxylamine 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 strong antihistaminic and anticholinergic activity, and doxylamine adds more of both. Together they can cause marked sedation, confusion, dry mouth, urinary retention and constipation. Older patients are particularly vulnerable.
How serious is the interaction between Doxepin and Doxylamine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid routine co-use of doxylamine with antidepressant-dose doxepin, especially in older adults. Monitor for sedation and anticholinergic toxicity and reduce doses if they occur.
What other medicines interact with Doxylamine?
MediHelp also lists interactions of Doxylamine with, for example, Belladonna and opium, Benzhydrocodone / acetaminophen, Brexanolone. The full list is on the Doxylamine page.
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