Trospium / Xanomeline and Cisapride: 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
Cisapride
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.
You've been prescribed cisapride, a medicine that helps your stomach and intestines move food along. The other medicine, Cobenfy, contains trospium, which is an anticholinergic. Anticholinergics tend to slow the gut down, which is the opposite of what cisapride is trying to do.
So when they're taken together, the trospium can work against the cisapride and make it less effective, meaning your stomach may not empty as well as it should. This is based mostly on how the drugs work in theory, not on strong studies. The good news is your care team can manage this. Let your pharmacist or doctor know you take both so they can keep an eye on how well the cisapride is working.
Effect: Potential loss of cisapride efficacy via pharmacodynamic antagonism.
- Mechanism: Cisapride is a prokinetic (5-HT4 agonist) that enhances GI motility; trospium is an antimuscarinic anticholinergic that reduces motility. The opposing pharmacodynamics blunt cisapride's prokinetic benefit. Neither agent's clearance drives this; it is PD, not PK.
- Direction: Reduced cisapride therapeutic effect.
- Onset: Delayed.
- Evidence: Theoretical; severity minor.
- Management: Monitor GI/prokinetic response. Dose may need individualization by the care team; consider alternatives if efficacy is inadequate. Note cisapride's separate QT/torsades risk warrants ECG caution independent of this interaction.
What happens
Loss of cisapride efficacy
Interaction Deep Dive
When an anticholinergic drug is taken together with cisapride, the gastrointestinal motility that cisapride typically promotes is likely to be opposed21.
Why it happens (mechanism)
Pharmacodynamic antagonism
How to manage this interaction
Here's how a care team usually handles this:
- Keep taking both exactly as prescribed unless your doctor tells you otherwise.
- Your team may watch more closely to see whether the cisapride is still helping your digestion and symptoms.
- If the cisapride isn't working as well as expected, your dose may be adjusted and individualized, or your prescriber may consider a different option.
Let your pharmacist or doctor know you take both medicines, and tell them if your original stomach symptoms come back or don't improve.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) The anticholinergic atropine fully suppressed the influence of cisapride on peristaltic contractions, regardless of whether atropine was given before or after cisapride. The lower esophageal sphincter pressure response to cisapride differed depending on the order in which the drugs were administered. When atropine was given first and cisapride afterward, cisapride produced no effect. When this order was reversed, atropine did not significantly inhibit the cisapride-stimulated lower esophageal sphincter pressure 1.
Common questions
Can I take Trospium / Xanomeline and Cisapride together?
Trospium can work against cisapride and make it less effective at moving your gut, so tell your care team you take both and let them know if your symptoms don't improve. This is a theoretical, minor concern that your team can manage by monitoring and adjusting as needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Trospium / Xanomeline and Cisapride interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Trospium / Xanomeline and Cisapride interaction managed?
Here's how a care team usually handles this: Keep taking both exactly as prescribed unless your doctor tells you otherwise. Your team may watch more closely to see whether the cisapride is still helping your digestion and symptoms. If the cisapride isn't working as well as expected, your dose may be adjusted and individualized, or your prescriber may consider a different option. Let your pharmacis… 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 Cisapride 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 (2)
Keep reading about Cisapride
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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