Diethylstilbestrol

⚠️ Warning: High doses of diethylstilbestrol (DES) in early pregnancy have caused clear cell vaginal carcinoma in female offspring 16–20 years later. 👉 It must never be used in pre-menopausal women.

💊 About

• A synthetic oestrogen, historically prescribed for pregnancy-related issues.
• Withdrawn for most uses due to carcinogenic potential.
• Now only used in the treatment of malignant disease.
• Check BNF here for the latest details.

⚙️ Mode of Action

• Acts as an oestrogen analogue.
• Suppresses testosterone production → useful in androgen-dependent cancers (e.g., prostate carcinoma).
• Also used in certain post-menopausal breast cancers.

🎯 Indications / Dose

• Prostate carcinoma: 1–3 mg daily.
• Post-menopausal breast carcinoma: 10–20 mg daily.

🤝 Interactions

• See BNF for detailed interactions (multiple CYP- and oestrogen-related drug effects).

⚠️ Cautions

• As per BNF – monitor cardiovascular, hepatic, and thrombotic risks carefully.
• Long-term exposure increases malignancy risk.

🚫 Contraindications

• Pregnancy, children.
• Oestrogen-dependent tumours (breast, endometrium).
• Undiagnosed vaginal bleeding, porphyria.
• Moderate–severe hypertension.
• Severe or active liver disease.
• Dyslipidaemia, history of MI, stroke, VTE.
• Sickle cell anaemia, untreated polycythaemia, pulmonary hypertension.

❗ Side Effects

• Gynaecomastia.
• Thromboembolic risk (DVT, PE, stroke).
• Fluid retention, hypertension.
• Nausea, weight gain, reduced libido.
• ⚠️ Clear cell vaginal / cervical carcinoma in offspring exposed in utero.

📚 References

• BNF: Diethylstilbestrol
• Diethylstilbestrol – StatPearls