Abiraterone and Tucatinib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Tucatinib
Abiraterone
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.
What happens
Increased tucatinib exposure and risk of toxicity
Interaction Deep Dive
Avoid concomitant use of tucatinib (CYP2C8 substrate) with a strong CYP2C8 inhibitor because increased tucatinib exposure may increase risk of toxicities. In a clinical study, concomitant use of tucatinib with gemfibrozil, a strong CYP2C8 inhibitor, resulted in a significant increase in tucatinib AUC and Cmax. If coadministration with a strong CYP2C8 inhibitor is required, reduce tucatinib to 100 mg orally twice daily. After discontinuation of the strong CYP2C8 inhibitor for 3 elimination half-lives, resume tucatinib dose that was taken prior to concomitant use1.
Why it happens (mechanism)
Inhibition of CYP2C8-mediated metabolism of tucatinib
Literature reports
1 report — tap to read
a) In a clinical study, coadministration of a single tucatinib 300 mg dose with steady-state gemfibrozil 600 mg twice daily (a strong CYP2C8 inhibitor) resulted in a ratio of tucatinib exposure with and without concomitant drug for AUC of 3 and Cmax of 1.6 1.
Common questions
Can I take Abiraterone and Tucatinib together?
Increased tucatinib exposure and risk of toxicity Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abiraterone and Tucatinib 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Abiraterone or Tucatinib 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: TUKYSA(TM) oral tablets, tucatinib oral tablets. Seattle Genetics Inc (per FDA), Bothell, WA, 2020. DailyMed
Keep reading about Tucatinib
Keep reading about Abiraterone
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:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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