Drug Interaction Report

Estramustine and Somatropin: Interaction Details

A pharmacist-reviewed analysis of the Estramustine and Somatropin interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Estramustine

Emcyt Emcyt®
+

Somatropin

Accretropin® Genotropin Genotropin ® Humatrope Humatrope® Norditropin Norditropin® Nutropin
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Moderate
Can be significant — usually manageable with monitoring.
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.

Of 34 documented Estramustine interactions, 6 are rated moderate — including this one.
Onset
unspecified
Evidence
theoretical
Severity
Moderate

What happens

Decreased somatropin efficacy

Interaction Deep Dive

Treatment with somatropin and oral estrogens may decrease the serum IGF-1 response to somatropin. Patients receiving oral estrogen may require higher somatropin dosages1.

Why it happens (mechanism)

Decreased serum IGF-1 response to somatropin

Common questions

Can I take Estramustine and Somatropin together?

Decreased somatropin efficacy Always confirm with your pharmacist or prescriber before making any change.

How serious is the Estramustine and Somatropin interaction?

It is rated moderate. Can be significant — usually manageable with 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 Estramustine or Somatropin 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 (1)

  1. Product Information: HUMATROPE(R) subcutaneous injection, somatropin rDNA origin subcutaneous injection. Lilly USA LLC (per FDA), Indianapolis, IN, 2019. DailyMed
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