Drug interactions
Nortriptyline + Thioridazine
Severity: Contraindicated
Nortriptyline and Thioridazine: contraindicated 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
Thioridazine inhibits CYP2D6 and raises nortriptyline concentrations, while both drugs prolong the QT interval. The combination raises risk of serious ventricular arrhythmias including torsades de pointes.
What this interaction means in plain words
Nortriptyline and Thioridazine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Nortriptyline belongs to Central Nervous System; Thioridazine belongs to Central Nervous System.
Why it happens
CYP2D6 inhibition by thioridazine raises nortriptyline levels, combined with additive QT prolongation.
What to do
Avoid the combination and select non-QT-prolonging alternatives. If it cannot be avoided, obtain ECG and electrolytes and monitor drug levels.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Nortriptyline and Thioridazine, 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.
Other interactions of Nortriptyline
- Disopyramide + Nortriptyline Contraindicated
- Dofetilide + Nortriptyline Contraindicated
- Dronedarone + Nortriptyline Contraindicated
- Ibutilide + Nortriptyline Contraindicated
- Isocarboxazid + Nortriptyline Contraindicated
- Methylene blue + Nortriptyline Contraindicated
Other interactions of Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Nortriptyline with Thioridazine?
MediHelp rates the interaction as contraindicated. Nortriptyline and Thioridazine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Thioridazine inhibits CYP2D6 and raises nortriptyline concentrations, while both drugs prolong the QT interval. The combination raises risk of serious ventricular arrhythmias including torsades de pointes.
How serious is the interaction between Nortriptyline and Thioridazine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and select non-QT-prolonging alternatives. If it cannot be avoided, obtain ECG and electrolytes and monitor drug levels.
What other medicines interact with Nortriptyline?
MediHelp also lists interactions of Nortriptyline with, for example, Disopyramide, Dofetilide, Dronedarone. The full list is on the Nortriptyline 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.
