Nintedanib and Phenytoin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Phenytoin
Nintedanib
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 nintedanib exposure
Interaction Deep Dive
Concomitant use of nintedanib (a P-gp and CYP3A4 substrate) with a P-gp and CYP3A4 inducer may result in decreased exposure of nintedanib. Coadministration of nintedanib with the P-gp and CYP3A4 inducer rifampin decreased nintedanib AUC and Cmax by approximately 50% compared with nintedanib administration alone in a drug interaction study. Therefore, it is recommended that concomitant use of nintedanib with a P-gp and CYP3A4 inducer be avoided1.
Why it happens (mechanism)
Induction of P-gp efflux transport and CYP3A4-mediated metabolism of nintedanib
Literature reports
1 report — tap to read
a) In a drug interaction study, coadministration of nintedanib with oral doses of the P-gp and CYP3A4 inducer rifampin resulted in decreased nintedanib AUC to 50.3% and Cmax to 60.3% compared with nintedanib administration alone 1.
Common questions
Can I take Nintedanib and Phenytoin together?
Reduced nintedanib exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nintedanib and Phenytoin 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 Nintedanib or Phenytoin 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: OFEV(R) oral capsules, nintedanib oral capsules. Boehringer Ingelheim Pharmaceuticals, Inc. (per Manufacturer), Ridgefield, CT, 2014. DailyMed
Keep reading about Phenytoin
Keep reading about Nintedanib
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.
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