Omeprazole and Voriconazole: 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
Voriconazole
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.
These two medicines slow down each other's breakdown in your body. Voriconazole (an antifungal) and omeprazole (a stomach acid reducer) both use the same liver pathways, so when you take them together, the levels of both drugs can climb higher than expected.
Higher omeprazole levels can add to stomach-related side effects, and higher voriconazole levels can raise the chance of side effects like vision changes, liver strain, or heart rhythm effects. The good news: this is well understood and your care team can manage it, often by adjusting your doses and keeping a closer eye on you. Please don't change anything on your own. Just talk with your pharmacist or doctor.
Effect: Bidirectional increase in exposure. Voriconazole is a strong CYP2C19/CYP3A4 inhibitor and reduces omeprazole clearance, raising omeprazole AUC. Omeprazole, itself a CYP2C19 inhibitor, reciprocally increases voriconazole exposure.
- Onset: Rapid
- Evidence: Established
- Severity: Major
Management: Manufacturer advises reducing omeprazole dose by one-half when initiating voriconazole in patients on omeprazole 40 mg or greater; consider adjustment in Zollinger-Ellison patients on high doses (up to 240 mg/day). Adjust voriconazole dose and monitor for adverse reactions (visual disturbances, hepatotoxicity, QT prolongation).
What happens
Increased omeprazole exposure an increased voriconazole exposure
Interaction Deep Dive
Do not combine omeprazole with voriconazole 1. Coadministration of omeprazole with a potent inhibitor of both CYP2C19 and CYP3A4, for example voriconazole, can raise omeprazole exposure. In individuals with Zollinger-Ellison's syndrome receiving elevated doses (as high as 240 mg/day), a dosage modification of omeprazole should be considered 2. In patients already taking omeprazole at doses of 40 mg or higher, the omeprazole dose should be cut in half when voriconazole therapy is started. In addition, giving voriconazole together with CYP2C19 inhibitors like omeprazole can raise voriconazole exposure as well. Adjust the voriconazole dose and watch for adverse reactions 3.
Why it happens (mechanism)
Inhibition of CYP2C19-substrate metabolism of omeprazole; inhibition of CYP2C19-mediated metabolism of voriconazole; inhibition of CYP3A4-substrate metabolism of omeprazole
How to manage this interaction
This interaction is well documented and very manageable with the right plan from your care team.
- Keep taking both exactly as prescribed unless your prescriber tells you otherwise.
- Your team may reduce your omeprazole dose (guidance suggests cutting it in half when omeprazole is 40 mg or more) and may adjust your voriconazole dose, tailored to you.
- Expect closer monitoring for voriconazole side effects such as vision changes, signs of liver trouble, or heart rhythm symptoms.
Ask your pharmacist or doctor before starting, stopping, or changing either drug, and report any new symptoms promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) An open, randomized, placebo-controlled, cross-over trial in healthy volunteers (n=18) determined that giving omeprazole together with voriconazole raised voriconazole Cmax and AUC concentrations; nevertheless, omeprazole produced no clinically relevant impact on voriconazole exposure and no adjustment of the voriconazole dose is required. Healthy male volunteers (mean age, 26.3 years, range, 20 to 40 years) were given an oral voriconazole loading dose of 400 mg twice daily on day 1, followed by voriconazole 200 mg twice daily on days 2 through 9 and voriconazole 200 mg once daily on day 10, together with either oral omeprazole 40 mg once daily or a matched placebo for 10 days. Following a washout of at least 7 days, the volunteers were crossed over to the alternate treatment arm. Combining omeprazole with the voriconazole loading dose did not produce a significant change in the Cmax, Tmax, or AUC of voriconazole relative to the addition of placebo. At steady-state, however, voriconazole Cmax and AUC concentrations rose by 15% and 41%, respectively. The Tmax was unchanged, and the mean Cmin was higher compared with voriconazole plus placebo; even so, none of these pharmacokinetic parameter changes were deemed clinically significant. Three volunteers in the study were poor metabolizers of CYP2C19, and one of these patients experienced a transient elevation of liver function tests while taking omeprazole and voriconazole and was withdrawn from the study. Additional treatment-related adverse effects included headache, abnormal vision, and photophobia 4.
b) When omeprazole (40 mg once daily for 7 days) was given together with voriconazole (400 mg every 12 hours for 1 day, followed by 200 mg daily for 6 days) in healthy volunteers, the steady-state Cmax and 24 hour AUC of omeprazole rose significantly, by 2 times and 4 times, respectively, compared with omeprazole administered without voriconazole 23.
Common questions
Can I take Omeprazole and Voriconazole together?
Voriconazole and omeprazole raise each other's blood levels, so your care team may lower your omeprazole dose, adjust your voriconazole, and monitor you more closely. Don't change doses yourself; check with your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Omeprazole and Voriconazole interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How is the Omeprazole and Voriconazole interaction managed?
This interaction is well documented and very manageable with the right plan from your care team. Keep taking both exactly as prescribed unless your prescriber tells you otherwise. Your team may reduce your omeprazole dose (guidance suggests cutting it in half when omeprazole is 40 mg or more) and may adjust your voriconazole dose, tailored to you. Expect closer monitoring for voriconazole side eff… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
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 Voriconazole 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 (4)
- Product Information: YOSPRALA(TM) oral delayed-release tablets, aspirin, omeprazole oral delayed-release tablets. Aralez Pharmaceuticals US Inc (per manufacturer), Princeton, NJ, 2016. DailyMed
- Product Information: PRILOSEC(R) delayed-release oral capsules, omeprazole delayed-release capsules. AstraZeneca,LP, Wilmington, DE, 2006. DailyMed
- Product Information: VFEND(R) oral tablets, oral suspension, intravenous injection, voriconazole oral tablets, oral suspension, intravenous injection. Roerig (per FDA), New York, NY, 2025. DailyMed
- Wood N, Tan K, Purkins L, et al: Effect of omeprazole on the steady-state pharmacokinetics of voriconazole. Br J Clin Pharmacol 2003; 56(Suppl 1):56-61. PubMed
Keep reading about Voriconazole
Keep reading about Omeprazole
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