Nafcillin Injection and Ripretinib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ripretinib
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
Decreased exposure of ripretinib and its active metabolite and reduction of antitumor activity
Interaction Deep Dive
Coadministration of ripretinib (a CYP3A substrate) with a moderate CYP3A inducer may decrease exposure of ripretinib and its active metabolite, which may decrease antitumor activity. Coadministration of ripretinib with efavirenz (a moderate CYP3A inducer) was predicted to decrease ripretinib exposure. Avoid concomitant use of ripretinib and moderate CYP3A inducers. If use is unavoidable, increase dosage of ripretinib to 150 mg twice daily and monitor for clinical response and tolerability. If the moderate CYP3A inducer is discontinued, resume ripretinib at 150 mg once daily 14 days after discontinuation of the moderate CYP3A inducer1.
Why it happens (mechanism)
Induction of CYP3A-mediated ripretinib metabolism
Literature reports
1 report — tap to read
a) Coadministration of ripretinib (a CYP3A substrate) with efavirenz (a moderate CYP3A inducer) was predicted to decrease ripretinib Cmax by 24% and decrease AUC(0 to infinity) by 56% in a study 1.
Common questions
Can I take Nafcillin Injection and Ripretinib together?
Decreased exposure of ripretinib and its active metabolite and reduction of antitumor activity Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nafcillin Injection and Ripretinib 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 Nafcillin Injection or Ripretinib 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: QINLOCK(R) oral tablets, ripretinib oral tablets. Deciphera Pharmaceuticals LLC (per manufacturer), Waltham, MA, 2021. DailyMed
Keep reading about Ripretinib
Keep reading about Nafcillin Injection
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.
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