Abemaciclib and Apalutamide: 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
Apalutamide
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.
Here's what's going on. Apalutamide (Erleada) speeds up a liver enzyme called CYP3A4. That same enzyme breaks down abemaciclib (Verzenio). So when you take them together, your body clears the abemaciclib faster than usual, which can leave less of it in your system. The worry is that your cancer treatment may not work as well as it should.
The good news is your care team knows how to handle this. They may choose a different medication, adjust your dose, or keep a closer eye on how you're doing. Please don't change anything on your own. Just talk with your oncologist or pharmacist so they can make the best plan for you.
Effect: Apalutamide is a strong CYP3A4 inducer; abemaciclib is a CYP3A4 substrate. Coadministration is expected to increase abemaciclib clearance, lowering its AUC and Cmax and risking reduced antineoplastic efficacy.
- Direction: reduced abemaciclib exposure (loss of effect)
- Mechanism: induction of CYP3A4-mediated metabolism
- Evidence: probable; severity major
- Onset: unspecified (enzyme induction is typically delayed, over days to weeks)
Management: Substitution of the CYP3A4 substrate is recommended during apalutamide therapy. If coadministration is unavoidable, monitor closely for loss of abemaciclib activity; dose may need individualized adjustment by the oncology team.
What happens
Reduced CYP3A4 substrate exposure
Interaction Deep Dive
Taking apalutamide together with CYP3A4 substrates can lower the exposure to those substrates. Study data show that giving apalutamide alongside midazolam (a CYP3A4 substrate) led to decreased apalutamide exposure. It is advised to replace any drug that is chiefly metabolized by CYP3A4 while a patient is receiving apalutamide. Should concurrent use be necessary, monitor the patient for reduced substrate activity1.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism by apalutamide
How to manage this interaction
What your care team may do:
- Consider substituting a medication that isn't heavily broken down by CYP3A4, since that is the preferred approach here.
- If both drugs are needed together, watch you more closely for signs that the abemaciclib may not be working as well.
- Adjust and individualize your dosing as your team sees fit.
What you should do: Keep taking both medications exactly as prescribed unless your team tells you otherwise. Let your pharmacist or oncologist know you are on both drugs, and report any changes in how you feel so they can keep your treatment on track.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) Administering a single dose of apalutamide together with midazolam, a CYP3A4 substrate, produced a 92% reduction in the AUC of midazolam 1.
Common questions
Can I take Abemaciclib and Apalutamide together?
Apalutamide can lower abemaciclib levels and make it less effective, so your oncology team may switch one drug or monitor you more closely. Do not stop or change either medication on your own. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Apalutamide 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 Apalutamide interaction managed?
What your care team may do: Consider substituting a medication that isn't heavily broken down by CYP3A4, since that is the preferred approach here. If both drugs are needed together, watch you more closely for signs that the abemaciclib may not be working as well. Adjust and individualize your dosing as your team sees fit. What you should do: Keep taking both medications exactly as prescribed unle… 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 Apalutamide 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: ERLEADA(R) oral tablets, apalutamide oral tablets. Janssen Products LP (per FDA), Horsham, PA, 2024. DailyMed
Keep reading about Apalutamide
Keep reading about Abemaciclib
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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