Dacomitinib and Trospium / Xanomeline: 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
Dacomitinib
Trospium / Xanomeline
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.
Here's what's going on. Cobenfy contains xanomeline, and your body breaks that down using an enzyme called CYP2D6. Dacomitinib (Vizimpro) slows that same enzyme down. When the enzyme works slower, the xanomeline can build up a bit more than usual.
Because of this, you might notice more of xanomeline's usual side effects, like nausea, upset stomach, vomiting, or feeling dizzy. The good news is that this concern is theoretical, meaning it's based on how the drugs work rather than reports of real problems. Please don't change anything on your own. Your care team can watch you closely and adjust things if needed.
Mechanism: Dacomitinib inhibits CYP2D6, which contributes significantly to xanomeline metabolism. Inhibition is expected to increase xanomeline exposure (AUC/Cmax) and the frequency/severity of xanomeline-related adverse effects (cholinergic effects such as nausea, vomiting, diarrhea, dizziness).
- Direction: increased xanomeline effect (neither is a relevant prodrug here).
- Severity: moderate. Onset: unspecified.
- Evidence: theoretical.
Management: If coadministered, monitor for increased frequency and/or severity of xanomeline adverse reactions. Dose may be individualized by the care team; consider closer clinical monitoring during concurrent use.
What happens
Increased xanomeline exposure and an increased risk on severity and frequency of xanomeline-related adverse reactions
Interaction Deep Dive
The metabolism of xanomeline relies substantially on CYP2D6. When xanomeline is given together with CYP2D6 inhibitors, xanomeline exposure may rise, potentially heightening the severity and frequency of adverse reactions linked to xanomeline. In cases of concurrent use, patients should be watched for an increase in the frequency and/or severity of xanomeline-related adverse reactions1.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated metabolism of xanomeline
How to manage this interaction
What your care team may do:
- Keep an eye out for more frequent or stronger xanomeline side effects (nausea, vomiting, diarrhea, dizziness) while you take both.
- Adjust and individualize your dosing if that becomes necessary.
- Monitor you more closely during the time you use them together.
What you can do:
- Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Tell your pharmacist or doctor if you notice new or worsening stomach upset, dizziness, or other symptoms so they can respond.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Dacomitinib and Trospium / Xanomeline together?
Dacomitinib can slow the breakdown of xanomeline (in Cobenfy), which may raise xanomeline levels and side effects; this is a theoretical concern your care team can manage with monitoring. Keep taking both as prescribed and report any new or worsening symptoms. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dacomitinib and Trospium / Xanomeline interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Dacomitinib and Trospium / Xanomeline interaction managed?
What your care team may do: Keep an eye out for more frequent or stronger xanomeline side effects (nausea, vomiting, diarrhea, dizziness) while you take both. Adjust and individualize your dosing if that becomes necessary. Monitor you more closely during the time you use them together. What you can do: Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Tel… 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.
Questions for your pharmacist
- Does my dose of Dacomitinib or Trospium / Xanomeline 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 anything you'd monitor while I'm on both?
References (1)
- Citation #1
Keep reading about Dacomitinib
Keep reading about Trospium / Xanomeline
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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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