Abemaciclib and Cyclosporine: 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
Cyclosporine
Abemaciclib
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.
Let me explain what's going on here. Cyclosporine can slow down the enzyme in your body (called CYP3A4) that breaks down abemaciclib (Verzenio), your cancer medicine. When that clean-up slows down, more abemaciclib can build up in your blood than expected.
That could make abemaciclib's usual side effects stronger, like diarrhea, tiredness, or a drop in your blood cell counts. The good news is that this is something your care team knows how to handle. They may watch you a little more closely and, if needed, adjust your abemaciclib dose. Please keep taking both medicines as prescribed and let your pharmacist or doctor know you take them together.
Effect: Cyclosporine, a moderate CYP3A4 inhibitor, may reduce CYP3A4-mediated metabolism of abemaciclib (a CYP3A4 substrate), increasing plasma concentrations of abemaciclib and its active metabolites and raising toxicity risk (diarrhea, neutropenia, hepatotoxicity, fatigue).
- Direction: increased abemaciclib exposure (AUC/Cmax)
- Evidence: theoretical
- Onset: unspecified
- Severity: moderate
Management: Monitor for adverse reactions. If coadministered, consider reducing abemaciclib in 50 mg increments per labeling (e.g., 150 mg BID to 100 mg BID, then 50 mg BID; 200 mg BID stepping down similarly). Discontinue if 50 mg BID is not tolerated. Dose should be individualized by the oncology team.
What happens
Increased abemaciclib plasma concentration
Interaction Deep Dive
When abemaciclib, a substrate of CYP3A4, is taken together with a moderate CYP3A4 inhibitor, the plasma concentrations of both abemaciclib and its active metabolite may rise, which can heighten toxicity. Should the two be given together, watch for adverse reactions and consider lowering the abemaciclib dose in 50-mg steps. For a patient on 150 mg twice daily, the first reduction is to 100 mg twice daily and the second to 50 mg twice daily; if 50 mg twice daily cannot be tolerated, stop the drug. For a patient on 200 mg twice daily, reduce first to 150 mg twice daily, then to 100 mg twice daily, then to 50 mg twice daily; discontinue if 50 mg twice daily is not tolerated1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated abemaciclib metabolism
How to manage this interaction
You can keep taking both medicines as prescribed. Because cyclosporine can raise abemaciclib levels, your care team simply watches more closely and tailors the dose to you.
- Monitoring: your team may check more often for side effects like diarrhea, low blood counts, or liver changes.
- Dose: the abemaciclib dose may be adjusted and individualized (typically lowered in 50 mg steps) if side effects appear.
- What to do: report new or worsening diarrhea, fever, unusual tiredness, or signs of infection to your pharmacist or oncologist.
Do not change either medicine on your own; let your care team guide any adjustments.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) Within drug interaction investigations, giving abemaciclib together with verapamil and diltiazem (moderate CYP3A inhibitors) is projected to raise the AUC of abemaciclib along with its active metabolites (M2, M18, and M20) by roughly 1.6-fold and 2.4-fold, respectively 1.
Common questions
Can I take Abemaciclib and Cyclosporine together?
Cyclosporine can raise abemaciclib levels and may increase side effects, but your oncology team can manage this by monitoring you and adjusting the abemaciclib dose if needed. Keep taking both as prescribed and report new side effects. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Cyclosporine 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 Abemaciclib and Cyclosporine interaction managed?
You can keep taking both medicines as prescribed. Because cyclosporine can raise abemaciclib levels, your care team simply watches more closely and tailors the dose to you. Monitoring: your team may check more often for side effects like diarrhea, low blood counts, or liver changes. Dose: the abemaciclib dose may be adjusted and individualized (typically lowered in 50 mg steps) if side effects app… 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 Cyclosporine 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)
- Product Information: VERZENIO(TM) oral tablets, abemaciclib oral tablets. Lilly USA LLC (per FDA), Indianapolis, IN, 2018. DailyMed
Keep reading about Cyclosporine
Keep reading about Abemaciclib
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