Mometasone and Atazanavir: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Atazanavir
Mometasone
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.
What happens
Increased mometasone exposure and an increased risk of mometasone-related adverse reactions
Interaction Deep Dive
Concomitant administration of atazanavir, a strong CYP3A4 inhibitor, together with mometasone, a CYP3A4 substrate, may increase mometasone exposure. Although no formal drug interaction studies have been performed with atazanavir and mometasone, coadministration of ketoconazole, also a strong CYP3A4 inhibitor, with mometasone demonstrated elevated plasma concentrations of mometasone and decreased plasma cortisol levels in a drug interaction study in healthy subjects. Caution is advised if concurrent use of these drugs is necessary1. Concomitant use may result in the development of systemic corticosteroid effects (eg, Cushing syndrome and adrenal suppression). Consider alternative therapy, including beclomethasone, prednisone, and prednisolone, especially for long-term use 2.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated mometasone metabolism by atazanavir
Literature reports
1 report — tap to read
a) Concomitant use of ketoconazole and mometasone resulted in increased mometasone plasma concentrations in a drug interaction study in 24 healthy subjects. An inhaled dose of mometasone furoate 400 mcg was administered twice daily for 9 days with concurrent administration of either ketoconazole 200 mg or placebo given twice daily on days 4 to 9. Mometasone furoate peak plasma concentrations, which were less than 150 picograms (pg)/mL for all subjects on day 3 prior to administration of ketoconazole or placebo, increased to greater than 200 pg/mL (range, 211 to 324 pg/mL) on day 9 in 4 of the 12 subjects in the ketoconazole treatment group 1.
Common questions
Can I take Mometasone and Atazanavir together?
Increased mometasone exposure and an increased risk of mometasone-related adverse reactions Always confirm with your pharmacist or prescriber before making any change.
How serious is the Mometasone 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 "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Mometasone 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 (2)
- Product Information: DULERA(R) inhalation aerosol, mometasone furoate formoterol fumarate dihydrate inhalation aerosol. Schering Corporation, Whitehouse Station, NJ, 2010. DailyMed
- Product Information: EVOTAZ(R) oral tablets, atazanavir cobicistat oral tablets. Bristol-Myers Squibb Company (per FDA), Princeton, NJ, 2023. DailyMed
Keep reading about Atazanavir
Keep reading about Mometasone
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.
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