Trospium / Xanomeline and Ranolazine: 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
Ranolazine
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.
Ranolazine (for chest pain) can slow down one of your body's liver enzymes, called CYP2D6, that helps break down certain other medicines. Xanomeline, one of the ingredients in Cobenfy, is handled partly by that same enzyme. So when they are taken together, the Cobenfy component may build up a bit more in your body, which could make its effects (and side effects) a little stronger.
The good news is this concern is mostly based on how these drugs work in theory, not on lots of real-world problems. Please don't change anything on your own. Your care team can watch how you feel and adjust your dose if needed. Just let your pharmacist or doctor know you take both.
Mechanism: Ranolazine is a moderate CYP2D6 inhibitor. Coadministration with a CYP2D6 substrate may reduce its metabolism and increase systemic exposure (AUC/Cmax). In a study, ranolazine 750 mg BID raised metoprolol exposure ~80% in extensive metabolizers.
- Direction: increased substrate exposure (potentiated effect/toxicity). Neither agent is a prodrug requiring CYP2D6 activation, so the effect is additive exposure, not loss of effect.
- Evidence: theoretical for this specific pairing.
- Severity/onset: major; onset unspecified.
- Management: lower substrate dose may be required; monitor for exaggerated pharmacologic/anticholinergic effects.
What happens
Increased CYP2D6 substrates exposure
Interaction Deep Dive
When ranolazine is given together with CYP2D6 substrates, the exposure to those substrates may rise, so reduced doses of the substrates could be needed. A drug interaction study showed that giving ranolazine 750 mg twice daily alongside a single 100 mg dose of immediate release metoprolol, which is a CYP2D6 substrate, raised metoprolol exposure by 80% in extensive CYP2D6 metabolizers, though no adjustment of the metoprolol dose was necessary. Regarding dextromethorphan, another CYP2D6 substrate, ranolazine partially blocks the production of its principal metabolite dextrorphan in extensive metabolizers1.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated metabolism by ranolazine
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Here is what a care team typically does with this combination:
- The dose of the affected medicine may need to be lowered and individualized to you.
- Your team may monitor you more closely for stronger-than-usual effects or side effects after starting both.
What to do: Tell your pharmacist and doctor that you take both ranolazine and Cobenfy. Report any new or increased symptoms (such as dizziness, slow heartbeat, dry mouth, or feeling unusually affected by the medicine) so your dose can be adjusted if needed.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a drug interaction study, giving ranolazine 750 mg twice daily together with a single dose of immediate release metoprolol (100 mg), a CYP2D6 substrate, produced an 80% rise in metoprolol exposure among extensive CYP2D6 metabolizers, without requiring any dose modification of metoprolol. In extensive metabolizers of dextromethorphan, a CYP2D6 substrate, ranolazine partially inhibits the formation of the primary metabolite dextrorphan 1.
Common questions
Can I take Trospium / Xanomeline and Ranolazine together?
Ranolazine can raise levels of medicines cleared by CYP2D6, so the Cobenfy component may have stronger effects; keep taking both as prescribed and ask your care team whether your dose needs adjusting or closer monitoring. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Trospium / Xanomeline and Ranolazine 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 Trospium / Xanomeline and Ranolazine interaction managed?
Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Here is what a care team typically does with this combination: The dose of the affected medicine may need to be lowered and individualized to you. Your team may monitor you more closely for stronger-than-usual effects or side effects after starting both. What to do: Tell your pharmacist and doctor that you… 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 Trospium / Xanomeline or Ranolazine 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: RANOLAZINE oral extended-release tablets, ranolazine oral extended-release tablets. Viona Pharmaceuticals Inc. (per Dailymed), Cranford, NJ, 2023. DailyMed
Keep reading about Ranolazine
Keep reading about Trospium / Xanomeline
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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