Dexamethasone Ophthalmic and Aprepitant: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Aprepitant
Dexamethasone Ophthalmic
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 dexAMETHasone exposure
Interaction Deep Dive
Coadministration of aprepitant and dexAMETHasone may result in increased dexAMETHasone exposure. When given concomitantly with an oral aprepitant, administer 50% of the recommended dexAMETHasone on Days 1 through 4, i.e., 6 mg orally on Day 1 followed by 4 mg orally on Days 1 through 4 for highly emetogenic cancer therapy (HEC) and 6 mg orally on Day 1 for moderately emetogenic cancer therapy (MEC)1. With concomitant administration of IV aprepitant or fosaprepitant regimen in adults, administer 50% of the recommended dexAMETHasone on Days 1 and 2, i.e., 6 mg orally on Day 1 followed by 4 mg orally on Day 2 for HEC and 6 mg orally on Day 1 for MEC 234.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated dexAMETHasone metabolism
Literature reports
2 reports — tap to read
a) Mean dexAMETHasone AUC was increased 2-fold on days 1 and 2 following oral dexAMETHasone 8 mg on days 1, 2, and 3 and a single fosaprepitant 150 mg IV dose on day 1 2.
b) Coadministration of aprepitant 125 mg orally on day 1 and 80 mg orally on days 2 through 5 with dexAMETHasone 20 mg orally on day 1 and 8 mg orally on days 2 through 5 increased the dexAMETHasone AUC by 2.2-fold on days 1 and 5 1.
Common questions
Can I take Dexamethasone Ophthalmic and Aprepitant together?
Increased dexAMETHasone exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dexamethasone Ophthalmic and Aprepitant interaction?
It is rated moderate. Can be significant — usually manageable with 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 strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
Questions for your pharmacist
- Does my dose of Dexamethasone Ophthalmic or Aprepitant 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 anything you'd monitor while I'm on both?
References (4)
- Product Information: EMEND(R) oral capsules, oral suspension, aprepitant oral capsules, oral suspension. Merck Sharp & Dohme Corp (per FDA), Whitehouse Station, NJ, 2019. DailyMed
- Product Information: CINVANTI(R) intravenous injection emulsion, aprepitant intravenous injection emulsion. Heron Therapeutics Inc (per FDA), San Diego, CA, 2019. DailyMed
- Product Information: EMEND(R) intravenous injection, fosaprepitant dimeglumine intravenous injection. Merck Sharp & Dohme Corp. (per FDA), Whitehouse Station, NJ, 2016. DailyMed
- Product Information: FOCINVEZ intravenous injection, fosaprepitant intravenous injection. Spes Pharmaceuticals Inc (per FDA), North Brunswick, NJ, 2023. DailyMed
Keep reading about Aprepitant
Keep reading about Dexamethasone Ophthalmic
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