Ziftomenib and Omeprazole: 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
Omeprazole
Ziftomenib
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. Omeprazole (Prilosec) lowers the amount of acid in your stomach. Ziftomenib (Komzifti), a cancer medicine, needs a normal, acidic stomach to dissolve and get absorbed properly. When the two are taken together, your body absorbs much less ziftomenib, so it may not work as well against your cancer.
This is an important interaction, but it's manageable. Please don't stop or change either medicine on your own. Let your cancer team and pharmacist know you take omeprazole. They can look at your acid reducer and pick the safest plan so your ziftomenib keeps doing its job.
Effect: Reduced ziftomenib exposure and potential loss of efficacy.
Mechanism: Omeprazole raises gastric pH, decreasing the pH-dependent solubility and absorption of ziftomenib. This is a PK (absorption) interaction, not enzyme-mediated.
- Magnitude: In DDI studies, PPI coadministration reduced ziftomenib AUC(0-inf) by ~53% and Cmax by ~70%.
- Direction: Decreased ziftomenib exposure/efficacy.
- Evidence: Probable; severity major.
- Management: Avoid coadministration of ziftomenib with PPIs. Consider alternative acid-suppression strategies per oncology guidance; individualize and monitor therapeutic response.
What happens
Reduced ziftomenib exposure and reduced efficacy of ziftomenib
Interaction Deep Dive
Do not give ziftomenib together with proton pump inhibitors, since doing so can lower ziftomenib exposure and thereby diminish the drug's effectiveness. Drug interaction research showed that when PPIs were administered with ziftomenib, the ziftomenib AUC(0-inf) fell by 53% and the Cmax dropped by 70%1.
Why it happens (mechanism)
Changes in gastric pH
How to manage this interaction
What your care team may do:
- Avoid using omeprazole (a proton pump inhibitor) together with ziftomenib, since it can substantially lower ziftomenib levels.
- Review whether you still need an acid reducer, or consider a different approach for stomach symptoms that your oncology team recommends.
- Watch how well your ziftomenib is working.
What you should do: Keep taking both exactly as prescribed for now, and do not stop either on your own. Tell your pharmacist and prescriber that you take omeprazole (or any heartburn or reflux medicine, including over-the-counter ones) so they can tailor the safest plan.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In drug interaction studies, giving proton pump inhibitors (PPIs) together with ziftomenib decreased ziftomenib AUC(0-inf) by 53% and Cmax by 70% 1.
Common questions
Can I take Ziftomenib and Omeprazole together?
Omeprazole can cut ziftomenib absorption by more than half and may make it less effective, so this combination is generally avoided. Tell your cancer team about any acid reducer you take so they can adjust your plan. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ziftomenib and Omeprazole 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 Ziftomenib and Omeprazole interaction managed?
What your care team may do: Avoid using omeprazole (a proton pump inhibitor) together with ziftomenib, since it can substantially lower ziftomenib levels. Review whether you still need an acid reducer, or consider a different approach for stomach symptoms that your oncology team recommends. Watch how well your ziftomenib is working. What you should do: Keep taking both exactly as prescribed for no… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Ziftomenib or Omeprazole 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: KOMZIFTI™ oral capsules, ziftomenib oral capsules. Kura Oncology, Inc (per manufacturer), San Diego, CA, 2025. DailyMed
Keep reading about Omeprazole
Keep reading about Ziftomenib
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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