Dexamethasone Injection and Cobicistat: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cobicistat
Dexamethasone Injection
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
Reduced cobicistat exposure and increased dexAMETHasone exposure
Interaction Deep Dive
Avoid coadministration of dexAMETHasone with cobicistat (a strong CYP3A4 inhibitor) or consider alternative medications that are not strong CYP3A4 inhibitors. If concomitant use of strong CYP3A4 inhibitors with dexAMETHasone cannot be avoided, closely monitor for adverse drug reactions1. Coadministration of cobicistat with systemic dexAMETHasone or other systemic corticosteroids that induce CYP3A may result in loss of therapeutic effect and development of resistance to cobicistat. Consider alternative corticosteroids. Alternative corticosteroids including beclomethasone, predniSONE, and prednisoLONE (for which PK and/or PD are less affected by strong CYP3A inhibitors relative to other steroids) should be considered, particularly for long term use 2.
Why it happens (mechanism)
Induction of CYP3A-mediated metabolism of cobicistat; inhibition of CYP3A-mediated metabolism of dexAMETHasone
Literature reports
1 report — tap to read
a) Coadministration of itraconazole (strong CYP3A4 inhibitor: 200 mg once daily x 4 days) with a single dose of oral dexAMETHasone (4.5 mg) increased dexAMETHasone AUC by 3.7-fold 1.
Common questions
Can I take Dexamethasone Injection and Cobicistat together?
Reduced cobicistat exposure and increased dexAMETHasone exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dexamethasone Injection and Cobicistat 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.
Questions for your pharmacist
- Does my dose of Dexamethasone Injection or Cobicistat 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: HEMADY(TM) oral tablets, dexamethasone oral tablets. Dexcel Pharma Technologies (per FDA), Boulder, CO, 2019. DailyMed
- Product Information: SYMTUZA(R) oral tablets, darunavir, cobicistat, emtricitabine, tenofovir alafenamide oral tablets. Janssen Products, LP (per FDA), Horsham, PA, 2023. DailyMed
Keep reading about Cobicistat
Keep reading about Dexamethasone Injection
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