Atrasentan and Nafcillin Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Nafcillin Injection
Atrasentan
No brand names on record
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 atrasentan exposure and reduced efficacy of atrasentan
Interaction Deep Dive
Avoid concomitant use of atrasentan with a strong or moderate CYP3A4 inducer. Coadministration of atrasentan (CYP3A4 substrate) with a moderate or strong CYP3A4 inducer may reduce atrasentan exposure, which may reduce the efficacy of atrasentan. In a drug interaction study, atrasentan Ctrough reduced by 90% following coadministration of a single dose of 10 mg atrasentan with rifAMPin (strong CYP3A4 inducer)1.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of atrasentan
Literature reports
1 report — tap to read
a) In a drug interaction study, atrasentan Ctrough reduced by 90% following coadministration of a single dose of 10 mg atrasentan with rifAMPin (strong CYP3A4 inducer) 1.
Common questions
Can I take Atrasentan and Nafcillin Injection together?
Reduced atrasentan exposure and reduced efficacy of atrasentan Always confirm with your pharmacist or prescriber before making any change.
How serious is the Atrasentan and Nafcillin Injection 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 Atrasentan or Nafcillin Injection 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: VANRAFIA(TM) oral tablets, atrasentan oral tablets. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2025. DailyMed
Keep reading about Nafcillin Injection
Keep reading about Atrasentan
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist