Omeprazole and Cannabidiol: 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
Cannabidiol
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. Cannabidiol (Epidiolex) can slow down a liver enzyme called CYP2C19, which is one of the pathways your body uses to break down omeprazole (Prilosec). When that enzyme is slowed, omeprazole can build up a bit higher in your body than usual.
In everyday terms, that could mean a stronger effect from your omeprazole and a slightly higher chance of side effects like headache, stomach upset, or diarrhea. This is mostly a theoretical concern based on how the drugs work, not a long list of real-world reports. The good news is your care team can easily manage this by adjusting your dose if needed, so please talk with your pharmacist or doctor before changing anything.
Mechanism: Cannabidiol is a moderate CYP2C19 inhibitor; omeprazole is a CYP2C19 substrate. Inhibition reduces omeprazole clearance, raising its exposure (AUC/Cmax).
Direction: Increased omeprazole exposure and increased risk of substrate-related adverse effects. Neither agent's active moiety depends on CYP2C19 activation, so effects are amplified, not reduced.
- Severity: Major (on file)
- Onset: Unspecified
- Evidence: Theoretical
Management: Consider omeprazole dose reduction as clinically appropriate; individualize and monitor for PPI-related adverse effects. Reassess if CBD dose changes.
What happens
Increased CYP2C19 substrate exposure and an increased risk of CYP2C19 substrate-related adverse reactions
Interaction Deep Dive
When cannabidiol, which acts as a moderate CYP2C19 inhibitor, is given together with CYP2C19 substrates, the exposure to those substrates may rise, potentially heightening the likelihood of adverse reactions. Where clinically appropriate, a reduction in the dosage of CYP2C19 substrates should be considered during concurrent use with cannabidiol1.
Why it happens (mechanism)
Inhibition of CYP2C19-substrate metabolism by cannabidiol
How to manage this interaction
What your care team may do:
- Consider reducing the omeprazole dose if clinically appropriate, tailored to you.
- Watch a bit more closely for side effects such as headache, nausea, or diarrhea.
What you should do:
- Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Tell your pharmacist or doctor that you take both, and mention any new or worsening symptoms.
- Ask before making any dose changes on your own.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Omeprazole and Cannabidiol together?
Cannabidiol can raise omeprazole levels by slowing its breakdown, so your care team may lower the omeprazole dose or watch you a little more closely. Keep taking both as prescribed and check with your pharmacist or doctor before making changes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Omeprazole and Cannabidiol 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 Cannabidiol interaction managed?
What your care team may do: Consider reducing the omeprazole dose if clinically appropriate, tailored to you. Watch a bit more closely for side effects such as headache, nausea, or diarrhea. What you should do: Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Tell your pharmacist or doctor that you take both, and mention any new or worsening symptoms. As… 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 Cannabidiol 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: EPIDIOLEX(R) oral solution, cannabidiol oral solution. Jazz Pharmaceuticals, Inc. (per FDA), Palo Alto, CA, 2025. DailyMed
Keep reading about Cannabidiol
Keep reading about Omeprazole
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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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