Abemaciclib and Givinostat: 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
Givinostat
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 broken down in your body by an enzyme called CYP3A4. Givinostat (Duvyzat) can gently slow that enzyme down in your gut. When the enzyme works slower, more abemaciclib can build up in your blood.
Because abemaciclib is a cancer medicine where the right level really matters, having a bit too much could mean more side effects, such as diarrhea, low blood counts, or fatigue. The good news is this is very manageable. Your care team can watch you more closely and adjust your dose if needed, so please don't stop or change either medicine on your own, just talk with your oncologist or pharmacist.
Mechanism: Givinostat is a weak inhibitor of intestinal CYP3A4 (demonstrated via midazolam exposure in healthy volunteers). Abemaciclib is a sensitive oral CYP3A4 substrate with a narrow therapeutic index.
Effect / direction: Reduced first-pass metabolism increases abemaciclib exposure (AUC/Cmax), raising the risk of dose-related toxicity (diarrhea, neutropenia, hepatotoxicity, fatigue).
- Evidence: Probable; based on a clinical DDI study using midazolam.
- Onset: Unspecified.
- Management: Monitor closely for abemaciclib adverse effects; individualize/reduce dose per clinical response and hematologic/hepatic parameters.
What happens
Increased CYP3A4 substrate exposure and an increased risk of CYP3A4 substrate-related adverse effects and toxicity
Interaction Deep Dive
When givinostat, which acts as a weak inhibitor of intestinal CYP3A4, is taken together with a CYP3A4 sensitive substrate that has a narrow therapeutic index, the exposure to the CYP3A4 substrate may rise, raising the likelihood of toxicity and adverse effects tied to that substrate. Healthy volunteers were enrolled in a clinical drug interaction study evaluating what happens when givinostat is given alongside other medications, and the findings showed that givinostat weakly inhibits the intestinal CYP3A4 enzyme, as measured by the exposure of the CYP3A4 substrate midazolam. Close monitoring is warranted whenever givinostat is combined with orally administered CYP3A4 sensitive substrates for which even a minor shift in substrate plasma concentration could result in serious toxicities1.
Why it happens (mechanism)
Inhibition of CYP3A4-substrate metabolism by givinostat
How to manage this interaction
How to manage this combination:
- Keep taking both as prescribed unless your care team tells you otherwise.
- Expect your team to monitor you more closely for abemaciclib side effects like diarrhea, low blood counts, liver changes, or unusual tiredness.
- Your abemaciclib dose may need to be adjusted and individualized by your oncologist based on how you respond.
- Report new or worsening symptoms promptly, and ask your pharmacist before adding any new medicines or supplements.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A clinical drug interaction study was performed in healthy volunteers to evaluate the effects of administering givinostat together with other medications, and the findings showed that givinostat weakly inhibits the intestinal CYP3A4 enzyme, as determined by the exposure of a CYP3A4 substrate (midazolam) 1.
Common questions
Can I take Abemaciclib and Givinostat together?
Givinostat can raise abemaciclib levels and increase side effects, so your care team may monitor you more closely and adjust your abemaciclib dose. Keep taking both as prescribed and report any new symptoms. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Givinostat 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 Givinostat interaction managed?
How to manage this combination: Keep taking both as prescribed unless your care team tells you otherwise. Expect your team to monitor you more closely for abemaciclib side effects like diarrhea, low blood counts, liver changes, or unusual tiredness. Your abemaciclib dose may need to be adjusted and individualized by your oncologist based on how you respond. Report new or worsening symptoms promptl… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Abemaciclib or Givinostat 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: DUVYZAT oral suspension, givinostat oral suspension. ITF Therapeutics, LLC (per FDA), Concord, MA, 2024. DailyMed
Keep reading about Abemaciclib
Keep reading about Givinostat
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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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