Drug Interaction Report

Lansoprazole and Atazanavir: Interaction Details

A pharmacist-reviewed analysis of the Lansoprazole and Atazanavir interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Atazanavir

Reyataz
+

Lansoprazole

Prevacid Prevacid® Prevacid® 24HR Prevacid® SoluTab®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 94 documented Lansoprazole interactions, 69 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

Reduced atazanavir exposure, reduced efficacy of atazanavir and development of resistance

Interaction Deep Dive

Concomitant use of atazanavir and a proton pump inhibitor (PPI) may result in substantially reduced atazanavir exposure, leading to a loss of atazanavir efficacy and development of HIV resistance. Therefore, coadministration is not recommended23, especially in treatment-experienced patients. Concomitant administration of multiple doses of atazanavir 400 mg once daily with omeprazole 40 mg once daily (2 hours before atazanavir) in 16 subjects resulted in decreases in atazanavir AUC by 94%, Cmax by 96%, and Cmin by 95%. If use in treatment-naive patients is required, do not exceed a PPI dose equivalent to omeprazole 20 mg and administer the PPI 12 hours prior to atazanavir 4.

Why it happens (mechanism)

Atazanavir solubility reduced by increased pH

Literature reports

1 report — tap to read

a) Concomitant administration of multiple doses of atazanavir 400 mg once daily with omeprazole 40 mg once daily (2 hours before atazanavir) in 16 subjects resulted in decreases in atazanavir AUC by 94%, Cmax by 96%, and Cmin by 95% 41.

Common questions

Can I take Lansoprazole and Atazanavir together?

Reduced atazanavir exposure, reduced efficacy of atazanavir and development of resistance Always confirm with your pharmacist or prescriber before making any change.

How serious is the Lansoprazole and Atazanavir 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 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 Lansoprazole or Atazanavir 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)

  1. Product Information: KONVOMEP(TM) powder for oral suspension, omeprazole sodium bicarbonate powder for oral suspension. Azurity Pharmaceuticals Inc (per manufacturer), Woburn, MA, 2022. DailyMed
  2. Product Information: DEXILANT(TM) oral delayed-release capsules, dexlansoprazole oral delayed-release capsules. Takeda Pharmaceuticals America, Inc. (per FDA), Deerfield, IL, 2014. DailyMed
  3. Product Information: NEXIUM(R) oral delayed-release capsules, suspension, esomeprazole magnesium oral delayed-release capsules, suspension. AstraZeneca LP (per FDA), Wilmington, DE, 2014. DailyMed
  4. Product Information: REYATAZ(R) oral capsules, oral powder, atazanavir oral capsules, oral powder. Bristol-Myers Squibb Company (per FDA), Princeton, NJ, 2023. DailyMed
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Atazanavir

Keep reading about Atazanavir

All Atazanavir interactions (179)
Also serious with: Encorafenib Irinotecan Lipid Complex Injection Lurasidone Lovastatin
Lansoprazole

Keep reading about Lansoprazole

All Lansoprazole interactions (94) Lansoprazole drug information
Also serious with: Rilpivirine Ziftomenib Belumosudil Octreotide Injection
Beyond drug–drug

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:

Atazanavir + Activated Charcoal Grapefruit St. John's Wort Acacia Rigidula Adrafinil African Wild Potato American Elder Astaxanthin + 144 more
Lansoprazole + Activated Charcoal Grapefruit St. John's Wort Acacia Rigidula Adrafinil African Wild Potato American Elder Artichoke + 145 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.