Dacomitinib and Nortriptyline: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Nortriptyline
No brand names on recordDacomitinib
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.
What happens
Increased exposure of the CYP2D6 substrate
Interaction Deep Dive
Avoid coadministration of dacomitinib and CYP2D6 substrates where minimal increases in concentration of the substrate may lead to serious or life-threatening toxicities. Coadministration of dacomitinib and dextromethorphan (a CYP2D6 substrate) increased dextromethorphan Cmax by 9.7-fold and AUC by 9.6-fold1.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated metabolism by dacomitinib
Literature reports
1 report — tap to read
a) Coadministration of a single 45 mg dose of dacomitinib increased dextromethorphan (a CYP2D6 substrate) Cmax by 9.7-fold and AUC by 9.6-fold 1.
Common questions
Can I take Dacomitinib and Nortriptyline together?
Increased exposure of the CYP2D6 substrate Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dacomitinib and Nortriptyline 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 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 Dacomitinib or Nortriptyline 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: VIZIMPRO(R) oral tablets, dacomitinib oral tablets. Pfizer Labs (per FDA), New York, NY, 2018. DailyMed
Keep reading about Nortriptyline
Keep reading about Dacomitinib
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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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