Drug Interaction Report

Enzalutamide and Avatrombopag: Interaction Details

A pharmacist-reviewed analysis of the Enzalutamide and Avatrombopag interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Enzalutamide

Xtandi
+

Avatrombopag

Doptelet Doptelet®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Jul 11, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 120 documented Enzalutamide interactions, 102 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

Decreased avatrombopag exposure

Interaction Deep Dive

Avatrombopag is metabolized by CYP2C9 and CYP3A4 and coadministration in a clinical trial (n=16) with rifampin (a moderate inducer of CYP2C9 and strong inducer of CYP3A4) significantly reduced avatrombopag AUC and t(1/2) by about half2. Because of risk for reduced avatrombopag efficacy, increase initial avatrombopag dosage to 40 mg orally once daily when used for chronic immune thrombocytopenia and concomitantly with a moderate or strong dual inducer of CYP2C9 and CYP3A4. In patients initiating a dual inducer while receiving avatrombopag, adjust avatrombopag dosage based on usual platelet count monitoring 1.

Why it happens (mechanism)

Induction of CYP2C9- and CYP3A4-mediated metabolism of avatrombopag

Literature reports

1 report — tap to read

a) Coadministration of single-dose avatrombopag 20 mg with steady-state rifampin (600 mg daily for 16 days; a moderate inducer of CYP2C9 and strong inducer of CYP3A) significantly reduced avatrombopag exposure in a trial in 16 healthy subjects. Avatrombopag AUC(0 to infinity) reduced 57% (90% confidence interval [CI], 0.47 to 0.62) and t(1/2) was significantly reduced to 9.77 hours (vs 20.3 hours with avatrombopag alone) 2.

Common questions

Can I take Enzalutamide and Avatrombopag together?

Decreased avatrombopag exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Enzalutamide and Avatrombopag 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 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 Enzalutamide or Avatrombopag 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 (2)

  1. Product Information: DOPTELET(R) oral tablets, avatrombopag oral tablets. Dova Pharmaceuticals Inc (per FDA), Durham, NC, 2019. DailyMed
  2. Nomoto M, Zamora CA, Schuck E, et al: Pharmacokinetic/pharmacodynamic drug-drug interactions of avatrombopag when coadministered with dual or selective CYP2C9 and CYP3A interacting drugs. Br J Clin Pharmacol 2018; 84(5):952-960. PubMed
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Enzalutamide

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Avatrombopag

Keep reading about Avatrombopag

All Avatrombopag interactions (35) Avatrombopag drug information
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Beyond drug–drug

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:

Enzalutamide + Activated Charcoal Alkanna Alpine Ragwort Black Tea Boneset Borage Butterbur Cannabidiol (cbd) + 41 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.