Elacestrant and Topotecan: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Topotecan
Elacestrant
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 topotecan exposure and risk of adverse events
Interaction Deep Dive
Concomitant use of oral topotecan (a breast cancer resistance protein (BCRP) substrate) and a BCRP inhibitor may increase systemic exposure of topotecan and increase the risk of adverse events. In a clinical study, following coadministration of a dual inhibitor of BCRP and P-gp, the exposure of topotecan increased approximately 2.5-fold. Concomitant use of orally administered topotecan and P-gp inhibitors should be avoided1.
Why it happens (mechanism)
Inhibition of breast cancer resistance protein-mediated efflux transport of topotecan
Literature reports
1 report — tap to read
a) Coadministration of escalating doses of a dual BCRP and P-gp inhibitor, resulted in an increase in the AUC(infinity) of topotecan lactone and total topotecan of approximately 2.5-fold compared with topotecan alone 1.
Common questions
Can I take Elacestrant and Topotecan together?
Increased topotecan exposure and risk of adverse events Always confirm with your pharmacist or prescriber before making any change.
How serious is the Elacestrant and Topotecan 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 Elacestrant or Topotecan 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: HYCAMTIN(R) oral capsules, topotecan oral capsules. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2018. DailyMed
Keep reading about Topotecan
Keep reading about Elacestrant
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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