Omeprazole and Itraconazole: 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
Itraconazole
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 can affect each other in two ways. Itraconazole (Sporanox) is an antifungal that needs an acidic stomach to be absorbed well. Omeprazole (Prilosec) lowers stomach acid, so it can leave your body absorbing less itraconazole, which may make the antifungal work less well against your infection.
At the same time, itraconazole can slow down how your body clears omeprazole, so omeprazole levels may climb and side effects like headache, stomach upset, or diarrhea could become more likely. The good news is your care team can manage this by adjusting doses and watching how you respond. Please don't change anything on your own, just check in with your pharmacist or doctor.
Bidirectional interaction (theoretical evidence).
- Itraconazole: absorption is pH-dependent. Omeprazole-induced gastric acid suppression reduces itraconazole dissolution and absorption, lowering itraconazole exposure and risking subtherapeutic antifungal levels (analogous data seen with ranitidine/antacids).
- Omeprazole: a CYP3A4 substrate; itraconazole is a potent CYP3A4 inhibitor, so omeprazole AUC/Cmax may rise, increasing dose-related adverse effects.
Onset: unspecified. Management: use with caution; monitor antifungal efficacy and omeprazole-related adverse reactions. Omeprazole dose reduction may be needed. Consider taking itraconazole with an acidic beverage per product labeling if clinically appropriate. Individualize under prescriber guidance.
What happens
Reduced itraconazole exposure, increased omeprazole exposure and an increased risk of omeprazole-related adverse effects
Interaction Deep Dive
When itraconazole is taken together with omeprazole (a proton pump inhibitor that also acts as a CYP3A4 substrate), itraconazole exposure may fall while omeprazole plasma concentrations may rise, potentially leading to a greater incidence of omeprazole-related adverse reactions. Caution is therefore advised whenever itraconazole is combined with agents that suppress acid secretion, including omeprazole. Watch for adverse reactions attributable to omeprazole, and a reduction in the omeprazole dose may be required1. A study found that when itraconazole was given alongside ranitidine and antacids, itraconazole serum concentrations were markedly lower than when itraconazole was administered on its own3.
Why it happens (mechanism)
Decreased gastrointestinal absorption of itraconazole due to suppression or neutralization of gastric pH; inhibition of CYP3A4-mediated metabolism of omeprazole
How to manage this interaction
If you've been prescribed both, keep taking them as directed unless your care team tells you otherwise. Here's how a team typically handles this:
- They may monitor whether your antifungal is working, since less itraconazole may be absorbed when stomach acid is reduced.
- They may watch for omeprazole side effects (headache, nausea, diarrhea, stomach discomfort) because omeprazole levels can rise.
- Your omeprazole dose may be adjusted and individualized by your prescriber if needed.
Tell your pharmacist or doctor about all your medicines, and report any new or worsening symptoms so they can tailor your treatment.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) In a study involving 30 healthy men, the uptake of itraconazole capsules was diminished when itraconazole 200 mg was taken with water following pretreatment with ranitidine 150 mg twice daily for 3 days, showing reductions in AUC(0 to 24) and Cmax of 39% +/- 37% and 42% +/- 39%, respectively. When itraconazole was given with cola after ranitidine pretreatment, itraconazole uptake resembled that seen when itraconazole was given by itself 2.
b) The systemic availability of itraconazole was assessed in 17 lung transplant recipients who were concurrently receiving ranitidine 150 mg every 12 hours along with antacids. Among patients given itraconazole 200 mg and 400 mg daily, the median serum concentrations were 0.5 mcg/mL and 3.5 mcg/mL, respectively. These serum values were markedly lower than those documented in earlier studies, which reported a median itraconazole serum concentration of 1.1 mcg/mL and 5.9 mcg/mL when itraconazole was given at daily doses of 200 mg and 400 mg, respectively 3.
Common questions
Can I take Omeprazole and Itraconazole together?
Omeprazole can lower itraconazole absorption (weakening the antifungal) while itraconazole can raise omeprazole levels (more side effects); keep taking both as prescribed and let your care team monitor and adjust the doses. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Omeprazole and Itraconazole 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 Itraconazole interaction managed?
If you've been prescribed both, keep taking them as directed unless your care team tells you otherwise. Here's how a team typically handles this: They may monitor whether your antifungal is working, since less itraconazole may be absorbed when stomach acid is reduced. They may watch for omeprazole side effects (headache, nausea, diarrhea, stomach discomfort) because omeprazole levels can rise. You… 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 Itraconazole 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 (3)
- Product Information: SPORANOX(R) oral capsules, itraconazole oral capsules. Janssen Pharmaceuticals Inc (per FDA), Titusville, NJ, 2022. DailyMed
- Product Information: SPORANOX(R) oral capsules, itraconazole oral capsules. Janssen Pharmaceuticals, Inc. (per DailyMed), Titusville, NJ, 2012. DailyMed
- Patterson TF, Peters J, Levine SM, et al: Systemic availability of itraconazole in lung transplantation. Antimicrob Agents Chemother 1996; 40:2217-2220. PubMed
Keep reading about Itraconazole
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:
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