Abemaciclib and Indinavir: 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
Indinavir
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.
Let's talk about taking indinavir and abemaciclib (Verzenio) together. Abemaciclib is a cancer medicine that your body clears using a liver enzyme called CYP3A4. Indinavir strongly blocks that same enzyme, so abemaciclib can build up higher than usual in your blood. That means a bigger chance of side effects like diarrhea, low blood counts, tiredness, or nausea.
The good news is this is very manageable. Your cancer team knows about this and can simply lower your abemaciclib dose while you're on indinavir, then raise it back afterward. Please don't change anything on your own. Just keep both as prescribed and check in with your oncologist or pharmacist.
Effect: Indinavir, a strong CYP3A4 inhibitor, reduces CYP3A4-mediated metabolism of abemaciclib, increasing plasma levels of abemaciclib and its active metabolites and raising toxicity risk (diarrhea, myelosuppression, hepatotoxicity, fatigue).
- Direction: Increased abemaciclib exposure (AUC/Cmax). Abemaciclib is the active drug, not a prodrug, so higher levels mean greater effect/toxicity.
- Evidence: Theoretical; mechanism-based.
- Onset: Unspecified.
- Management: If starting dose was 200 or 150 mg BID, reduce to 100 mg BID. If already reduced to 100 mg BID for adverse reactions, reduce to 50 mg BID. On stopping indinavir, resume prior dose after 3 to 5 inhibitor half-lives. Monitor for abemaciclib toxicity.
What happens
Increased abemaciclib plasma concentration
Interaction Deep Dive
Taking abemaciclib together with a strong CYP3A4 inhibitor can raise plasma concentrations of abemaciclib along with its active metabolite, potentially increasing toxicity. When these agents are given together and the initial abemaciclib dose was 200 mg or 150 mg twice daily, lower the abemaciclib dose to 100 mg twice daily. For patients whose dose has already been cut to 100 mg twice daily because of adverse reactions, reduce the abemaciclib dose further to 50 mg twice daily. Once the strong CYP3A inhibitor is stopped, raise the abemaciclib dose (following 3-5 half-lives of the inhibitor) back to the dose given prior to starting the strong inhibitor1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated abemaciclib metabolism
How to manage this interaction
This interaction is manageable and your care team has a clear plan for it.
- Keep taking both exactly as prescribed unless your oncologist tells you otherwise.
- Your team will likely reduce your abemaciclib dose while you are on indinavir, and then increase it back to your previous dose after indinavir is stopped (once the inhibitor has cleared).
- Expect closer monitoring for side effects such as diarrhea, low blood counts, fatigue, or nausea.
Tell your pharmacist or prescriber about all your medicines, and report any new or worsening side effects promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) Drug interaction studies predict that giving abemaciclib together with itraconazole (a strong CYP3A inhibitor) will raise the AUC of abemaciclib along with its active metabolites (M2, M18 and M20) by 2.2-fold 1.
b) In drug interaction studies conducted in cancer patients, administering a single 50 mg dose of abemaciclib (0.3 times the approved 150 mg dose) alongside clarithromycin 500 mg twice daily (a strong CYP3A inhibitor) raised the AUC(0 to infinity) of abemaciclib plus its active metabolites (M2, M18, and M20) by 1.7-fold relative to abemaciclib given alone 1.
Common questions
Can I take Abemaciclib and Indinavir together?
Indinavir can raise abemaciclib levels and side-effect risk by blocking its breakdown, but your oncology team can safely manage this by lowering the abemaciclib dose while you're on indinavir and monitoring you more closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Indinavir 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 Indinavir interaction managed?
This interaction is manageable and your care team has a clear plan for it. Keep taking both exactly as prescribed unless your oncologist tells you otherwise. Your team will likely reduce your abemaciclib dose while you are on indinavir, and then increase it back to your previous dose after indinavir is stopped (once the inhibitor has cleared). Expect closer monitoring for side effects such as diar… 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 Indinavir 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, 2017. DailyMed
Keep reading about Indinavir
Keep reading about Abemaciclib
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