Duvelisib and Nafcillin Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Duvelisib
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 duvelisib exposure
Interaction Deep Dive
Concomitant use of duvelisib (CYP3A4 substrate) with a moderate CYP3A4 inducer decreases duvelisib exposure, which may decrease duvelisib efficacy. Coadministration of a single dose of duvelisib in healthy subjects reviewing etravirine increased duvelisib Cmax and AUC by 16% and 35%, respectively. Avoid concomitant use of duvelisib and a moderate CP3A4 inducer. If coadministration cannot be avoided, increase the dose of duvelisib on day 12 of coadministration (initial dose, 25 mg orally twice daily increase to 40 mg twice daily; initial dose, 15 mg orally twice daily increase to 25 mg twice daily). After the moderate CYP3A4 inducer has been discontinued for at least 14 days, resume duvelisib at the dose taken prior to initiating the moderate CYP3A4 inducer1.
Why it happens (mechanism)
Induction of CYP3A4-mediated duvelisib metabolism
Literature reports
1 report — tap to read
a) Coadministration of etravirine 200 mg twice daily for 12 days (moderate CYP3A inducer) with a single oral 25-mg dose of duvelisib decreased duvelisib Cmax by 16% and AUC by 35% in healthy adults 1.
Common questions
Can I take Duvelisib and Nafcillin Injection together?
Decreased duvelisib exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Duvelisib 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 Duvelisib 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: COPIKTRA(R) oral capsules, duvelisib oral capsules. Secura Bio Inc (per FDA), Las Vegas, NV, 2021. DailyMed
Keep reading about Duvelisib
Keep reading about Nafcillin Injection
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