Omeprazole and Avacopan: 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
Avacopan
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. Avacopan (Tavneos) can slow down one of your body's main drug-processing pathways, called CYP3A4. Omeprazole (Prilosec) is partly broken down by that same pathway. So when you take them together, the omeprazole may build up a little higher than usual, which could mean stronger effects or more side effects from it.
The good news is this is a theoretical concern based mostly on how the drugs behave in studies, not a proven problem with omeprazole specifically. Your care team can easily manage it by adjusting your dose if needed and keeping an eye on how you feel. Please don't stop or change either medicine on your own, just check in with your pharmacist or doctor.
Mechanism: Avacopan inhibits CYP3A4, reducing metabolism of CYP3A4 substrates and increasing their systemic exposure. Omeprazole is partly a CYP3A4 substrate (also CYP2C19), so its exposure may rise.
- Direction: Increased omeprazole exposure (AUC/Cmax).
- Magnitude: Not established for omeprazole. Illustrative avacopan data: simvastatin AUC up 3.53-fold, midazolam AUC up ~1.55-fold.
- Onset: Unspecified.
- Evidence: Theoretical for this pair.
- Management: Consider dose reduction of the CYP3A4 substrate; individualize and monitor for exaggerated effects/adverse events.
What happens
Increased CYP3A4 substrate exposure
Interaction Deep Dive
Taking avacopan together with a CYP3A4 substrate can raise the exposure of that substrate. When simvastatin (a CYP3A4 substrate) was given alongside avacopan at 60 mg daily for 7 days following food, the simvastatin AUC rose 3.53-fold and its Cmax rose 3.20-fold. Likewise, when midazolam (a CYP3A4 substrate) was administered with avacopan at 30 mg daily for 11 days on an empty stomach, the AUC and Cmax of simvastatin increased 1.55-fold and 1.81-fold respectively. Reducing the dose of CYP3A4 substrates should be considered when they are given together with avacopan1.
Why it happens (mechanism)
Inhibition of CYP3A4-substrate metabolism by avacopan
How to manage this interaction
How to handle this: Keep taking both medicines exactly as prescribed unless your care team tells you otherwise.
- Your team may lower the dose of the affected medicine (here, omeprazole) if needed, tailored to you.
- They may watch you a bit more closely for stronger-than-usual effects or side effects.
- Tell your pharmacist or prescriber about any new or bothersome symptoms.
- Share a full list of everything you take, since avacopan can affect other CYP3A4-processed drugs too.
This is a manageable interaction that your care team can adjust for.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) Giving simvastatin (a CYP3A4 substrate) together with avacopan, dosed at 60 mg daily for 7 days after food, raised the AUC and Cmax of simvastatin by 3.53-fold and 3.20-fold respectively 1.
b) Giving midazolam (a CYP3A4 substrate) together with avacopan, dosed at 30 mg daily for 11 days on an empty stomach, raised the AUC and Cmax of simvastatin by 1.55-fold and 1.81-fold respectively 1.
Common questions
Can I take Omeprazole and Avacopan together?
Avacopan can raise omeprazole levels by slowing its CYP3A4 breakdown, so your care team may lower the dose or monitor you more closely. Keep taking both as prescribed and check in before making any changes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Omeprazole and Avacopan 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 Avacopan interaction managed?
How to handle this: Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Your team may lower the dose of the affected medicine (here, omeprazole) if needed, tailored to you. They may watch you a bit more closely for stronger-than-usual effects or side effects. Tell your pharmacist or prescriber about any new or bothersome symptoms. Share a full list of everyt… 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 Avacopan 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: TAVNEOS(R) oral capsules, avacopan oral capsules. ChemoCentryx Inc (per FDA), Thousand Oaks, CA, 2024. DailyMed
Keep reading about Avacopan
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist