Drug interactions
Dexamethasone + Fosaprepitant
Severity: Moderate
Dexamethasone and Fosaprepitant: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Aprepitant, the active form of fosaprepitant, raises dexamethasone exposure substantially. This is relevant in antiemetic regimens where the dexamethasone dose is intentionally reduced.
What this interaction means in plain words
Dexamethasone and Fosaprepitant can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Dexamethasone belongs to Endocrine; Fosaprepitant belongs to Gastrointestinal Tract.
Why it happens
Aprepitant is a moderate CYP3A4 inhibitor that decreases dexamethasone clearance.
What to do
Reduce the oral dexamethasone dose in antiemetic regimens as per labeling (about half) when given with fosaprepitant, and monitor for steroid adverse effects.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Dexamethasone
- Bcg vaccine live + Dexamethasone Contraindicated
- Dexamethasone + Mifepristone Contraindicated
- Dexamethasone + Rilpivirine Contraindicated
- Dexamethasone + Smallpox vaccine live Contraindicated
- Dexamethasone + Varicella virus vaccine live Contraindicated
- Dexamethasone + Yellow fever vaccine Contraindicated
Other interactions of Fosaprepitant
- Flibanserin + Fosaprepitant Contraindicated
- Fosaprepitant + Pimozide Contraindicated
- Alprazolam + Fosaprepitant Moderate
- Amiodarone + Fosaprepitant Moderate
- Amobarbital + Fosaprepitant Moderate
- Apalutamide + Fosaprepitant Moderate
Frequently asked questions
Can I take Dexamethasone with Fosaprepitant?
MediHelp rates the interaction as moderate. Dexamethasone and Fosaprepitant can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Aprepitant, the active form of fosaprepitant, raises dexamethasone exposure substantially. This is relevant in antiemetic regimens where the dexamethasone dose is intentionally reduced.
How serious is the interaction between Dexamethasone and Fosaprepitant?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce the oral dexamethasone dose in antiemetic regimens as per labeling (about half) when given with fosaprepitant, and monitor for steroid adverse effects.
What other medicines interact with Dexamethasone?
MediHelp also lists interactions of Dexamethasone with, for example, Bcg vaccine live, Mifepristone, Rilpivirine. The full list is on the Dexamethasone page.
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