Estradiol and Cosyntropin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Estradiol
Cosyntropin
No brand names on record
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 cortisol exposure
Interaction Deep Dive
Do not administer estrogen containing drugs 4 to 6 weeks before cosyntropin testing to allow cortisol binding globulin levels to return to levels within the reference range. Estrogen may elevate the total plasma cortisol levels due to an increased cortisol binding globulin levels resulting in inaccurate test results when cosyntropin is used as a diagnostic agent in the screening of adrenocortical insufficiency. Alternatively, concomitant measurement of cortisol binding globulin at the time of testing should be done; if cortisol binding globulin levels are elevated, consider that the plasma total cortisol levels are inaccurate1.
Why it happens (mechanism)
Increased cortisol binding globulin levels
Common questions
Can I take Estradiol and Cosyntropin together?
Increased cortisol exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Estradiol and Cosyntropin 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 Estradiol or Cosyntropin 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 (1)
- Product Information: CORTROSYN(R) intramuscular intravenous injection, cosyntropin intramuscular intravenous injection. Amphastar Pharmaceuticals, Inc (per FDA), Rancho Cucamonga, CA, 2023.
Keep reading about Estradiol
Keep reading about Cosyntropin
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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