Nafcillin Injection and Mobocertinib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Mobocertinib
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 mobocertinib exposure and risk of reduction of the anti-tumor activity of mobocertinib
Interaction Deep Dive
Concomitant use of mobocertinib (CYP3A substrate) with a strong or moderate CYP3A inducer should be avoided because decreased mobocertinib plasma concentrations may occur, which may reduce the anti-tumor activity of mobocertinib. Coadministration of mobocertinib with multiple doses of rifampin (a strong CYP3A inducer) or efavirenz (a moderate CYP3A inducer) is predicted to decrease the steady-state combined molar AUC of mobocertinib and its active metabolites by 92% and 58%, respectively1.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of mobocertinib
Literature reports
2 reports — tap to read
a) Coadministration of mobocertinib with multiple doses of efavirenz (a moderate CYP3A inducer) is predicted to decrease the steady-state combined molar AUC of mobocertinib and its active metabolites by 58% 1.
b) Coadministration of mobocertinib with multiple doses of rifampin (a strong CYP3A inducer) is predicted to decrease the steady-state combined molar AUC of mobocertinib and its active metabolites by 92% 1.
Common questions
Can I take Nafcillin Injection and Mobocertinib together?
Reduced mobocertinib exposure and risk of reduction of the anti-tumor activity of mobocertinib Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nafcillin Injection and Mobocertinib 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 Mobocertinib 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: EXKIVITY(TM) oral capsules, mobocertinib oral capsules. Takeda Pharmaceuticals America Inc (per FDA), Lexington, MA, 2021.
Keep reading about Mobocertinib
Keep reading about Nafcillin Injection
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