Drug interactions
Doxepin + Trimipramine
Severity: Major
Doxepin and Trimipramine: major interaction.
Last updated Sources: US FDA label
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
Two tricyclic antidepressants given together add up their anticholinergic, sedative, cardiac conduction, QT and serotonergic effects. They also compete for the same metabolic pathways, which can raise levels of either drug.
What this interaction means in plain words
Doxepin and Trimipramine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Doxepin belongs to Dermatology; Trimipramine belongs to Central Nervous System.
Why it happens
Duplicate pharmacodynamic effects, plus competition for CYP2D6 and CYP2C19 metabolism.
What to do
Avoid combining two tricyclics; use one agent at an optimized dose. If a switch is needed, cross-taper with ECG and symptom monitoring.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Trimipramine
- Disopyramide + Trimipramine Contraindicated
- Dofetilide + Trimipramine Contraindicated
- Ibutilide + Trimipramine Contraindicated
- Isocarboxazid + Trimipramine Contraindicated
- Pentamidine + Trimipramine Contraindicated
- Phenelzine + Trimipramine Contraindicated
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 Trimipramine?
MediHelp rates the interaction as major. Doxepin and Trimipramine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Two tricyclic antidepressants given together add up their anticholinergic, sedative, cardiac conduction, QT and serotonergic effects. They also compete for the same metabolic pathways, which can raise levels of either drug.
How serious is the interaction between Doxepin and Trimipramine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combining two tricyclics; use one agent at an optimized dose. If a switch is needed, cross-taper with ECG and symptom monitoring.
What other medicines interact with Trimipramine?
MediHelp also lists interactions of Trimipramine with, for example, Disopyramide, Dofetilide, Ibutilide. The full list is on the Trimipramine page.
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