Trospium / Xanomeline and Felodipine: 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
Felodipine
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 felodipine (a blood pressure pill) along with Cobenfy, which contains xanomeline. Xanomeline can briefly slow down an enzyme in your gut called CYP3A4 that normally helps break down felodipine. When that enzyme is slowed, a little more felodipine can get into your body than usual.
What this means for you: you might notice more of felodipine's usual effects, like dizziness, flushing, headache, swollen ankles, or a faster heartbeat. This is based mostly on theory, not strong real-world reports, so please don't worry. Keep taking both exactly as prescribed, and let your pharmacist or doctor know if you feel any of these more strongly.
Mechanism: Xanomeline transiently inhibits intestinal (gut-wall) CYP3A4, not systemic CYP3A4. Felodipine is a sensitive oral CYP3A4 substrate with high first-pass metabolism, so reduced gut-wall metabolism can raise its bioavailability, AUC, and Cmax.
Direction: Increased felodipine exposure and increased risk/severity of dose-related adverse effects (hypotension, dizziness, flushing, headache, peripheral edema, reflex tachycardia).
- Onset: unspecified
- Evidence: theoretical
- Management: monitor for enhanced antihypertensive/vasodilatory effects; check BP and heart rate. Dose may be individualized by the care team if increased effects appear.
What happens
Increased oral sensitive CYP3A4 substrate exposure and an increased risk on severity and frequency of sensitive CYP3A4 substrate-related adverse reactions
Interaction Deep Dive
Within the gut, xanomeline produces a temporary, local inhibition of CYP3A4, without affecting the enzyme systemically. When xanomeline is taken together with oral medications that are sensitive CYP3A4 substrates, the exposure to those oral sensitive CYP3A4 substrates may rise. As a result, the frequency and/or severity of adverse reactions caused by these substrates may increase. During concurrent administration, patients should be monitored for any rise in the frequency and/or severity of adverse reactions associated with oral drugs that are sensitive substrates of CYP3A41.
Why it happens (mechanism)
Inhibition of CYP3A4-substrate metabolism by xanomeline
How to manage this interaction
Good news: this is a manageable interaction, and you should keep taking both medications as prescribed unless your care team tells you otherwise.
Here's what usually happens:
- Your team may monitor you more closely for stronger felodipine effects, such as low blood pressure, dizziness, flushing, headache, or ankle swelling.
- If those effects show up, your felodipine dose may be adjusted and individualized by your prescriber.
What to do: Tell your pharmacist or doctor if you feel lightheaded, unusually flushed, or notice new swelling. Don't stop or change either medicine on your own.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Trospium / Xanomeline and Felodipine together?
Xanomeline (in Cobenfy) can raise felodipine levels by slowing its breakdown in the gut, so watch for stronger effects like dizziness, flushing, or swelling and report them; your care team can adjust the dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Trospium / Xanomeline and Felodipine 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 Trospium / Xanomeline and Felodipine interaction managed?
Good news: this is a manageable interaction, and you should keep taking both medications as prescribed unless your care team tells you otherwise. Here's what usually happens: Your team may monitor you more closely for stronger felodipine effects, such as low blood pressure, dizziness, flushing, headache, or ankle swelling. If those effects show up, your felodipine dose may be adjusted and individu… 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 Felodipine 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 Felodipine
Keep reading about Trospium / Xanomeline
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