Abemaciclib and Lumacaftor: 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
Lumacaftor
No brand names on recordAbemaciclib
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 is what is going on. Abemaciclib (Verzenio) is a cancer medicine that your body breaks down using a liver enzyme called CYP3A4. Lumacaftor speeds that enzyme up, so it can clear abemaciclib out of your body faster. That means the level of your cancer medicine, and its active form, may drop too low.
The concern here is that abemaciclib may not work as well as it should, which really matters for a cancer treatment. This is based on theory and on similar drugs, not on direct studies of these two together. Please do not stop or change either medicine on your own. Talk with your oncologist or pharmacist, who can pick a safer combination for you.
Mechanism: Lumacaftor is a strong CYP3A4 inducer; abemaciclib is a CYP3A4 substrate. Enzyme induction accelerates abemaciclib metabolism, lowering plasma concentrations of the parent drug and its active metabolites (PK interaction, reduced exposure).
- Direction: Decreased abemaciclib exposure, risk of reduced antineoplastic efficacy.
- Magnitude: Rifampin (strong inducer) reduced abemaciclib AUC by ~67%; a comparable effect is anticipated.
- Onset: Unspecified; induction typically develops over days to weeks.
- Evidence: Theoretical, extrapolated from strong-inducer data.
Management: Avoid concomitant use. Select an alternative agent that does not induce CYP3A4.
What happens
Decreased abemaciclib plasma concentration
Interaction Deep Dive
When abemaciclib is taken together with a potent CYP3A4 inducer, plasma concentrations of abemaciclib and its active metabolite can fall, potentially reducing therapeutic effectiveness. Study data showed that giving abemaciclib alongside rifampin (a strong CYP3A4 inducer) lowered abemaciclib exposure by 67%. This combination should not be used; alternative agents ought to be considered1.
Why it happens (mechanism)
Induction of CYP3A4-mediated abemaciclib metabolism
How to manage this interaction
What your care team may do:
- Generally avoid using these two together, because a strong CYP3A4 inducer can substantially lower abemaciclib levels and reduce how well it fights cancer.
- Consider an alternative medicine that does not speed up abemaciclib's breakdown.
What you should do:
- Keep taking both exactly as prescribed until you have spoken with your prescriber. Do not stop your cancer treatment on your own.
- Tell your oncologist and pharmacist that you are taking both, and ask whether a substitution is appropriate for you.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In drug interaction trials involving healthy participants, giving a single 200 mg dose of abemaciclib together with rifampin 600 mg daily (a potent CYP3A inducer) lowered the AUC(0 to infinity) of abemaciclib along with its active metabolites (M2, M18, and M20) by 67% 1.
Common questions
Can I take Abemaciclib and Lumacaftor together?
Lumacaftor can markedly lower abemaciclib levels and may make the cancer treatment less effective, so this combination is best avoided. Ask your oncologist or pharmacist about an alternative before changing anything. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Lumacaftor 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 Lumacaftor interaction managed?
What your care team may do: Generally avoid using these two together, because a strong CYP3A4 inducer can substantially lower abemaciclib levels and reduce how well it fights cancer. Consider an alternative medicine that does not speed up abemaciclib's breakdown. What you should do: Keep taking both exactly as prescribed until you have spoken with your prescriber. Do not stop your cancer treatment… 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 Lumacaftor 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: VERZENIO(TM) oral tablets, abemaciclib oral tablets. Lilly USA LLC (per FDA), Indianapolis, IN, 2017. DailyMed
Keep reading about Lumacaftor
Keep reading about Abemaciclib
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