Drug interactions
Amitriptyline + Trifluoperazine
Severity: Major
Amitriptyline and Trifluoperazine: 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
Both agents can prolong the QT interval, increasing the risk of ventricular arrhythmias such as torsades de pointes. Additive sedation and anticholinergic effects are also likely, and the phenothiazine may raise tricyclic levels.
What this interaction means in plain words
Amitriptyline and Trifluoperazine 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 QT prolongation, with possible CYP2D6 inhibition by the phenothiazine raising amitriptyline exposure.
What to do
Avoid if possible, or obtain an ECG and monitor electrolytes. Use the lowest effective doses and watch for anticholinergic and sedative effects.
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 Amitriptyline and Trifluoperazine, 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 Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Trifluoperazine?
MediHelp rates the interaction as major. Amitriptyline and Trifluoperazine 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. Both agents can prolong the QT interval, increasing the risk of ventricular arrhythmias such as torsades de pointes. Additive sedation and anticholinergic effects are also likely, and the phenothiazine may raise tricyclic levels.
How serious is the interaction between Amitriptyline and Trifluoperazine?
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 if possible, or obtain an ECG and monitor electrolytes. Use the lowest effective doses and watch for anticholinergic and sedative effects.
What other medicines interact with Amitriptyline?
MediHelp also lists interactions of Amitriptyline with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Amitriptyline 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.
