Kratom and Abemaciclib: 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
Kratom
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 kratom along with your cancer medicine abemaciclib (Verzenio). Your body uses an enzyme called CYP3A to break down abemaciclib and clear it out. Kratom appears to slow that enzyme down, which means more of the abemaciclib can build up in your body than expected. This is more likely with higher kratom doses or if you use it regularly.
Higher levels could mean stronger side effects from abemaciclib, like diarrhea, tiredness, or low blood counts. The good news is this is very manageable. Please tell your oncology team and pharmacist about any kratom use so they can watch you closely and adjust things if needed.
Effect: Kratom is a probable CYP3A inhibitor; abemaciclib is a CYP3A4 substrate. Co-use may reduce abemaciclib clearance and increase its exposure (AUC/Cmax), raising the risk of dose-related toxicity.
- Direction: Increased abemaciclib effect/toxicity (not a prodrug; parent drug is active).
- Magnitude: Not quantified; likely dose- and duration-dependent (higher/chronic kratom use).
- Onset: Unspecified. Evidence: Probable.
- Monitor: Diarrhea, fatigue, hepatotoxicity, neutropenia (CBC, LFTs). Abemaciclib dose may be adjusted and individualized by the care team; consider avoiding kratom.
What happens
Increased CYP3A substrate exposure
Interaction Deep Dive
When kratom (a CYP3A inhibitor) is taken together with a substrate of CYP3A, the exposure to that substrate may rise, particularly at elevated kratom doses or during long-term use1. Careful monitoring is advised 2.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism by kratom
How to manage this interaction
Keep taking your abemaciclib exactly as prescribed, and do not start or stop anything on your own. Here is how a care team usually handles this:
- Tell your oncologist and pharmacist about any kratom use, including how much and how often.
- They may monitor you more closely for abemaciclib side effects (diarrhea, fatigue, blood counts, liver tests).
- Your abemaciclib dose may be adjusted and individualized by your team if needed.
- They may suggest avoiding kratom, since higher or regular use raises the risk.
Report new or worsening side effects promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) An open-label crossover study in healthy adults (N=12) assessed the effect of taking a single low dose of kratom tea (2 g) alongside oral midazolam (a CYP3A probe substrate; 2.5 mg) and oral dextromethorphan (a CYP2D6 probe substrate; 30 mg). Kratom produced a modest rise in the midazolam geometric mean AUC (1.39; 90% CI, 1.23 to 1.57) and Cmax (1.5; 90% CI, 1.32 to 1.7); no impact on dextromethorphan AUC or Cmax was seen. The half life of midazolam was not significantly changed by concurrent kratom use, indicating inhibition of first-pass metabolism, mainly CYP3A within the intestine. The participants (median age, 30 years) had prior kratom exposure and agreed to refrain from concomitant medications and botanical or other natural products (including kratom) throughout the study 1.
Common questions
Can I take Kratom and Abemaciclib together?
Kratom can slow how your body clears abemaciclib, letting it build up and increase side effects, so tell your oncology team about any kratom use and let them monitor you and adjust the dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Kratom and Abemaciclib 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 Kratom and Abemaciclib interaction managed?
Keep taking your abemaciclib exactly as prescribed, and do not start or stop anything on your own. Here is how a care team usually handles this: Tell your oncologist and pharmacist about any kratom use, including how much and how often. They may monitor you more closely for abemaciclib side effects (diarrhea, fatigue, blood counts, liver tests). Your abemaciclib dose may be adjusted and individual… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Kratom or Abemaciclib 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 (2)
- Tanna RS, Nguyen JT, Hadi DL, et al: Clinical assessment of the drug interaction potential of the psychotropic natural product kratom. Clin Pharmacol Ther 2023; 113(6):1315-1325. PubMed
- Dhoble LR, Gour A, McCurdy CR, et al: Evaluating the drug interactions in kratom usage: clinical application. Expert Opin Drug Metab Toxicol 2025; 21(8):949-959. DOI
Keep reading about Kratom
Keep reading about Abemaciclib
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