Armodafinil 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
Armodafinil
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. Armodafinil (Nuvigil) can slow down one of the liver enzymes that breaks down omeprazole (Prilosec). When that enzyme works slower, more omeprazole stays in your body. Studies showed roughly a 40% increase in the amount of omeprazole floating around.
For most people this is a modest change. It could make omeprazole's effects, and any side effects like headache or stomach upset, a bit stronger. The good news is this is very manageable. Your care team can adjust your omeprazole dose if needed and keep an eye on how you're doing. Keep taking both as prescribed and just let your pharmacist or doctor know you're on both.
Mechanism: Armodafinil is a moderate CYP2C19 inhibitor. Omeprazole is a CYP2C19 substrate (not a prodrug in this context), so inhibition reduces its clearance and increases exposure.
Magnitude: A single 400 mg armodafinil dose with 40 mg omeprazole produced roughly a 40% increase in omeprazole AUC.
- Direction: increased omeprazole exposure (PK)
- Onset: unspecified
- Evidence: probable
- Management: Use caution; omeprazole dose reduction may be warranted and individualized. Monitor for dose-related PPI effects.
What happens
Increased omeprazole exposure
Interaction Deep Dive
Armodafinil, the R-enantiomer of modafinil, has the potential to moderately inhibit the activity of the CYP2C19 isozyme. When a single 400-mg dose of armodafinil was given together with a 40-mg dose of omeprazole, which is a substrate of CYP2C19, the systemic exposure to omeprazole rose by roughly 40%. Caution is therefore advised if these two drugs are taken at the same time, and it may be necessary to lower the omeprazole dose1.
Why it happens (mechanism)
Inhibition of CYP2C19-mediated omeprazole metabolism
How to manage this interaction
This is manageable with your care team. The documented approach is to use caution together, since omeprazole levels can rise about 40%.
- Keep taking both medications exactly as prescribed unless told otherwise.
- Your omeprazole dose may need to be adjusted and individualized by your care team.
- Your team may monitor you a bit more closely for stronger omeprazole effects or side effects.
- Tell your pharmacist or prescriber that you take both, and mention any new or increased symptoms.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Armodafinil and Omeprazole together?
Armodafinil can raise omeprazole levels by about 40% by slowing its breakdown, so your care team may lower the omeprazole dose or watch you more closely. Keep taking both as prescribed and let your pharmacist or doctor know you're on both. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Armodafinil and Omeprazole interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Armodafinil and Omeprazole interaction managed?
This is manageable with your care team. The documented approach is to use caution together, since omeprazole levels can rise about 40%. Keep taking both medications exactly as prescribed unless told otherwise. Your omeprazole dose may need to be adjusted and individualized by your care team. Your team may monitor you a bit more closely for stronger omeprazole effects or side effects. Tell your pha… 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 Armodafinil 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 anything you'd monitor while I'm on both?
References (1)
- Product Information: NUVIGIL(TM) oral tablets, armodafinil oral tablets. Cephalon,Inc, Frazer, PA, 2007. DailyMed
Keep reading about Armodafinil
Keep reading about Omeprazole
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