Nortriptyline and Amitriptyline: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Amitriptyline
Nortriptyline
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Both of these medicines are tricyclic antidepressants, and they work in very similar ways. Taking them together isn't something doctors usually do. The main concern is that each one can, on its own, affect the timing of your heartbeat (something called the QT interval). When you take both, that effect can add up and, in rare cases, lead to an irregular heart rhythm.
Here's the reassuring part: this is a theoretical concern, meaning it's based on how the drugs work rather than lots of reported cases. If you've been prescribed both, please keep taking them as directed and check in with your pharmacist or doctor, who can watch your heart health and adjust things as needed.
Interaction: Additive risk of QT-interval prolongation when amitriptyline and nortriptyline are combined. Both are tricyclic antidepressants with intrinsic cardiac effects (sodium-channel and repolarization effects); notably, nortriptyline is the active metabolite of amitriptyline via CYP-mediated demethylation, so co-administration is pharmacologically redundant and rarely intentional.
- Direction: Additive PD effect, increased cardiac risk.
- Evidence: Theoretical.
- Severity: Major.
- Onset: Unspecified.
Management: Avoid the combination where possible. If co-prescribed, use caution, consider baseline and follow-up ECG, monitor electrolytes (K+, Mg++), and review other QT-prolonging agents. Individualize dosing with the care team.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
It is not standard clinical practice to administer amitriptyline together with nortriptyline. Nevertheless, should these two agents be given concomitantly, caution is advised because of the possibility of additive QT interval effects and a heightened risk of serious cardiovascular events1.
Why it happens (mechanism)
Additive effects on the QT interval
How to manage this interaction
What your care team may do:
- Reassess whether both drugs are truly needed, since they are very similar and this combination is uncommon.
- Monitor your heart more closely, which may include an ECG to check your heart rhythm.
- Review your other medications for any that also affect the QT interval.
- Individualize and adjust your doses as appropriate.
What you should do: Keep taking both exactly as prescribed unless told otherwise. Tell your pharmacist or doctor if you feel fainting, dizziness, palpitations, or an irregular heartbeat, and mention any new medicines you start.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Nortriptyline and Amitriptyline together?
Combining amitriptyline and nortriptyline can add up their effects on heart rhythm (QT prolongation), so this pairing is uncommon and warrants caution; keep taking both as prescribed and let your care team monitor and adjust. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nortriptyline and Amitriptyline interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Nortriptyline and Amitriptyline interaction managed?
What your care team may do: Reassess whether both drugs are truly needed, since they are very similar and this combination is uncommon. Monitor your heart more closely, which may include an ECG to check your heart rhythm. Review your other medications for any that also affect the QT interval. Individualize and adjust your doses as appropriate. What you should do: Keep taking both exactly as prescr… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Nortriptyline or Amitriptyline need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Product Information: amitriptyline HCl oral tablet, amitriptyline HCl oral tablet. RemedyRepack Inc. (per DailyMed), Indiana, PA, 2010. DailyMed
Keep reading about Amitriptyline
Keep reading about Nortriptyline
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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