Nafcillin Injection and Zanubrutinib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Zanubrutinib
Nafcillin Injection
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
Reduced zanubrutinib exposure and reduced efficacy of zanubrutinib
Interaction Deep Dive
Avoid concomitant use of zanubrutinib (a CYP3A substrate) and a moderate CYP3A inducer as it may reduce zanubrutinib exposure, which may reduce zanubrutinib efficacy. In drug interaction studies, coadministration of multiple doses of rifabutin (moderate CYP3A inducer) decreased the zanubrutinib Cmax by 48% and AUC by 44%. Coadministration of multiple doses of efavirenz (moderate CYP3A inducer) is predicted to decrease zanubrutinib Cmax by 58% and AUC by 60%. If these inducers cannot be avoided, increase zanubrutinib dosage to 320 mg twice daily. After discontinuation of a moderate CYP3A inducer, resume previous dose of zanubrutinib1.
Why it happens (mechanism)
Induction of CYP3A-mediated metabolism of zanubrutinib
Literature reports
1 report — tap to read
a) In drug interaction studies, coadministration of multiple doses of rifabutin (moderate CYP3A inducer) decreased the zanubrutinib Cmax by 48% and AUC by 44%. Coadministration of multiple doses of efavirenz (moderate CYP3A inducer) is predicted to decrease zanubrutinib Cmax by 58% and AUC by 60% 1.
Common questions
Can I take Nafcillin Injection and Zanubrutinib together?
Reduced zanubrutinib exposure and reduced efficacy of zanubrutinib Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nafcillin Injection and Zanubrutinib 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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Nafcillin Injection or Zanubrutinib 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: BRUKINSA(R) oral capsules, oral tablets, zanubrutinib oral capsules, oral tablets. BeOne Medicines USA, Inc. (per FDA), Pennington, NJ, 2025. DailyMed
Keep reading about Zanubrutinib
Keep reading about Nafcillin Injection
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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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