Drug interactions
Doxepin + Imipramine
Severity: Major
Doxepin and Imipramine: 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 anticholinergic, sedative, cardiac conduction and QT effects, and serotonergic toxicity is possible. Each can also inhibit the metabolism of the other, raising overall tricyclic exposure.
What this interaction means in plain words
Doxepin and Imipramine 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; Imipramine belongs to Central Nervous System.
Why it happens
Additive pharmacodynamic effects (QT prolongation, anticholinergic, serotonergic) together with competition for CYP2D6 and CYP2C19 metabolism.
What to do
Avoid combining two tricyclics; use a single agent at an optimized dose. If overlap occurs during cross-titration, monitor ECG and for anticholinergic or serotonergic toxicity.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Doxepin and Imipramine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
Other interactions of Imipramine
- Dronedarone + Imipramine Contraindicated
- Imipramine + Isocarboxazid Contraindicated
- Imipramine + Phenelzine Contraindicated
- Imipramine + Pimozide Contraindicated
- Imipramine + Rasagiline Contraindicated
- Imipramine + Safinamide 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 Imipramine?
MediHelp rates the interaction as major. Doxepin and Imipramine 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 anticholinergic, sedative, cardiac conduction and QT effects, and serotonergic toxicity is possible. Each can also inhibit the metabolism of the other, raising overall tricyclic exposure.
How serious is the interaction between Doxepin and Imipramine?
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 a single agent at an optimized dose. If overlap occurs during cross-titration, monitor ECG and for anticholinergic or serotonergic toxicity.
What other medicines interact with Imipramine?
MediHelp also lists interactions of Imipramine with, for example, Dronedarone, Isocarboxazid, Phenelzine. The full list is on the Imipramine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
