Drug interactions
Imipramine + Protriptyline
Severity: Major
Imipramine and Protriptyline: major 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
Concurrent use of two tricyclic antidepressants duplicates therapy and increases the risk of anticholinergic toxicity, seizures, serotonin toxicity and QT/QRS prolongation. Imipramine may also raise protriptyline levels through CYP2D6 competition.
What this interaction means in plain words
Imipramine and Protriptyline 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.
Why it happens
Additive pharmacodynamic effects on cardiac ion channels, monoamine reuptake and muscarinic receptors, with shared CYP2D6 metabolism.
What to do
Avoid combining tricyclics and use a single agent. If a switch is needed, cross-taper and obtain an ECG in at-risk patients.
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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Other interactions of Imipramine
- Dronedarone + Imipramine Contraindicated
- Imipramine + Isocarboxazid Contraindicated
- Imipramine + Phenelzine Contraindicated
- Imipramine + Pimozide Contraindicated
- Imipramine + Rasagiline Contraindicated
- Imipramine + Safinamide Contraindicated
Frequently asked questions
Can I take Imipramine with Protriptyline?
MediHelp rates the interaction as major. Imipramine and Protriptyline 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. Concurrent use of two tricyclic antidepressants duplicates therapy and increases the risk of anticholinergic toxicity, seizures, serotonin toxicity and QT/QRS prolongation. Imipramine may also raise protriptyline levels through CYP2D6 competition.
How serious is the interaction between Imipramine and Protriptyline?
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 tricyclics and use a single agent. If a switch is needed, cross-taper and obtain an ECG in at-risk patients.
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.
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