Abemaciclib and Taurursodiol: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Abemaciclib
Taurursodiol
No brand names on record
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. Abemaciclib (Verzenio) is your cancer medicine, and your body breaks it down using an enzyme called CYP3A4. Taurursodiol (often combined with sodium phenylbutyrate) can speed up that enzyme. When the enzyme works faster, your body may clear the abemaciclib more quickly, so there could be less of it in your blood than intended.
For a cancer treatment, that matters, because you want enough medicine on board to do its job. The good news is this concern is based on theory, not a lot of real-world reports. Please don't change anything on your own. Your care team can watch this closely and adjust your plan if needed.
Effect: Potential decreased exposure of abemaciclib, a CYP3A4 substrate.
Mechanism: Sodium phenylbutyrate/taurursodiol may induce CYP3A4, increasing abemaciclib metabolism and lowering plasma concentrations (reduced AUC/Cmax), risking loss of antineoplastic efficacy.
- Direction: Reduced abemaciclib effect (inducer + active-drug substrate; not a prodrug).
- Onset: Unspecified; enzyme induction is typically delayed (days).
- Evidence: Theoretical.
- Severity: Major.
Management: Avoid the combination where reduced substrate levels could compromise efficacy. If co-used, monitor clinical/oncologic response; dose may need individualized adjustment by the oncology team.
What happens
Decreased exposure of the CYP3A4 substrate
Interaction Deep Dive
When sodium phenylbutyrate/taurursodiol, which acts as a CYP3A4 inducer, is taken together with a CYP3A4 substrate, exposure to that substrate may be reduced. Do not combine it with CYP3A4 substrates for which even a minor shift in the substrate's plasma concentration could cause serious toxicities or a loss of efficacy1.
Why it happens (mechanism)
Induction of CYP3A4 substrate metabolism by sodium phenylbutyrate/taurursodiol
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. This concern is theoretical, but because abemaciclib is a cancer treatment, keeping the right amount in your body matters.
- Tell your oncologist and pharmacist that you take (or are starting) taurursodiol.
- Your team may prefer to avoid this combination, or may monitor your response more closely.
- Your abemaciclib dose may need to be adjusted and individualized by your care team.
- Report any new or worsening symptoms so your team can respond.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abemaciclib and Taurursodiol together?
Taurursodiol may speed up how your body clears abemaciclib, possibly making the cancer medicine less effective, so let your oncology team know and let them decide whether to avoid the combination or monitor you closely. Do not change either medicine on your own. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Taurursodiol 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 Abemaciclib and Taurursodiol interaction managed?
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. This concern is theoretical, but because abemaciclib is a cancer treatment, keeping the right amount in your body matters. Tell your oncologist and pharmacist that you take (or are starting) taurursodiol. Your team may prefer to avoid this combination, or may monitor your response more closely. Your abemaci… 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 Abemaciclib or Taurursodiol 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: RELYVRIO(TM) oral powder for suspension, sodium phenylbutyrate taurursodiol oral powder for suspension. Amylyx Pharmaceuticals Inc (per FDA), Cambridge, MA, 2022.
Keep reading about Abemaciclib
Keep reading about Taurursodiol
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