Omeprazole and Dabrafenib: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Dabrafenib
Omeprazole
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.
Here's what's going on. Dabrafenib (Tafinlar) can speed up an enzyme in your liver called CYP2C19. Your acid-reducer omeprazole (Prilosec) is broken down by that same enzyme. So when you take them together, your body may clear the omeprazole faster than usual, which could make it work less well at controlling stomach acid.
This is based on theory and how these drugs behave, not on strong real-world reports, so please don't worry. Don't change anything on your own. Just let your pharmacist or doctor know you take both. If your heartburn or reflux symptoms creep back, that's the thing to mention so your care team can adjust your plan.
Mechanism: Dabrafenib is a moderate CYP2C19 inducer; omeprazole is a sensitive CYP2C19 substrate. Concurrent use may induce omeprazole metabolism, lowering its plasma exposure (AUC/Cmax) and potentially reducing acid-suppressant efficacy.
- Direction: reduced omeprazole effect
- Onset: unspecified (enzyme induction is typically delayed, days to weeks)
- Evidence: theoretical
- Severity on file: major
Management: Consider an alternative acid-suppression strategy, or if co-administration is unavoidable, monitor for loss of efficacy (recurrent reflux/dyspepsia symptoms). Dosing may need individualization by the care team.
What happens
Reduced CYP2C19 sensitive substrate exposure
Interaction Deep Dive
When dabrafenib is given at the same time as sensitive CYP2C19 substrates, the plasma levels of those substrates can fall, potentially causing them to lose efficacy. If this combination cannot be avoided, replace the affected drugs with alternatives or watch patients for any reduction in the effectiveness of these medications1.
Why it happens (mechanism)
Induction of CYP2C19-mediated metabolism by dabrafenib
How to manage this interaction
The good news: your care team can manage this by watching how well your omeprazole is working and tailoring your treatment.
- Keep taking both exactly as prescribed unless your prescriber tells you otherwise.
- Watch for returning symptoms like heartburn, reflux, or stomach discomfort, which could signal the omeprazole is working less well.
- Tell your pharmacist or doctor that you take both. Your team may adjust the acid-reducer dose, switch to a different option, or monitor you more closely.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Omeprazole and Dabrafenib together?
Dabrafenib may speed up how your body clears omeprazole, so the omeprazole could work less well; keep taking both as prescribed and tell your care team if reflux or heartburn symptoms return. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Omeprazole and Dabrafenib 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 is the Omeprazole and Dabrafenib interaction managed?
The good news: your care team can manage this by watching how well your omeprazole is working and tailoring your treatment. Keep taking both exactly as prescribed unless your prescriber tells you otherwise. Watch for returning symptoms like heartburn, reflux, or stomach discomfort, which could signal the omeprazole is working less well. Tell your pharmacist or doctor that you take both. Your team… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Omeprazole or Dabrafenib 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: TAFINLAR(R) oral capsules, tablets for suspension, dabrafenib oral capsules, tablets for suspension. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2023. DailyMed
Keep reading about Dabrafenib
Keep reading about Omeprazole
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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