Abemaciclib and Ceritinib: 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
Ceritinib
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.
These two cancer medicines can affect each other. Ceritinib can slow down the liver enzyme (called CYP3A) that normally breaks down abemaciclib. When that clean-up slows, more abemaciclib can build up in your body. That can mean stronger side effects, like diarrhea, low blood counts, tiredness, or nausea.
The good news is your cancer team knows how to handle this. They may adjust your abemaciclib dose or watch you more closely with lab work and check-ins. Please don't change or stop either drug on your own. Just keep taking them as prescribed and let your pharmacist or oncologist know about any new or worsening side effects.
Effect: Ceritinib is a CYP3A4 inhibitor; abemaciclib is a CYP3A4 substrate. Co-administration is expected to increase abemaciclib exposure (AUC/Cmax), raising the risk of dose-related toxicity (diarrhea, neutropenia, fatigue, hepatotoxicity).
- Mechanism: inhibition of CYP3A-mediated metabolism of abemaciclib.
- Direction: increased substrate exposure (neither drug is a prodrug).
- Severity/evidence: major; theoretical (mechanism-based).
- Onset: unspecified.
Management: Avoid concomitant use where feasible, particularly given abemaciclib's narrow therapeutic margin. If unavoidable, consider abemaciclib dose reduction and monitor closely for toxicity (CBC, LFTs, GI symptoms).
What happens
Increased exposure of CYP3A substrate
Interaction Deep Dive
Do not combine ceritinib with a CYP3A substrate that has a narrow therapeutic index, because doing so may raise the substrate's exposure along with its adverse effects. When such a combination is unavoidable, a reduction in the dose of the CYP3A substrate should be considered1.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism by ceritinib
How to manage this interaction
Your care team can manage this safely. Because ceritinib can raise abemaciclib levels, they will look at whether both are truly needed together.
- They may avoid using them together if there is a suitable alternative.
- If both are needed, they may reduce your abemaciclib dose and individualize it for you.
- They may monitor you more closely for side effects such as diarrhea, low blood counts, or fatigue.
What you should do: keep taking both exactly as prescribed, and don't adjust anything yourself. Tell your pharmacist or oncologist about any new or worsening side effects so they can act early.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abemaciclib and Ceritinib together?
Ceritinib can raise abemaciclib levels and side effects, so your oncology team will typically avoid the combination or lower the abemaciclib dose and watch you closely. Keep taking both as prescribed and report any new side effects. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Ceritinib 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 Ceritinib interaction managed?
Your care team can manage this safely. Because ceritinib can raise abemaciclib levels, they will look at whether both are truly needed together. They may avoid using them together if there is a suitable alternative. If both are needed, they may reduce your abemaciclib dose and individualize it for you. They may monitor you more closely for side effects such as diarrhea, low blood counts, or fatigu… 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 Ceritinib 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: ZYKADIA(TM) oral capsules, ceritinib oral capsules. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2014. DailyMed
Keep reading about Ceritinib
Keep reading about Abemaciclib
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