Synthetic non-steroidal oestrogen (legacy) Pregnancy: Contraindicated in pregnancy - diethylstilbestrol is a known human teratogen and is contraindicated in pre-menopausal women. High doses in the first trimester are associated with vaginal carcinoma, urogenital abnormalities and reduced fertility in female offspring, and an increased risk of hypospadias in male offspring (SPC 4.6)

Diethylstilbestrol

Brand names: DES (special import)

Diethylstilbestrol is a synthetic non-steroidal oestrogen now used rarely, principally as a hormonal treatment for advanced prostate cancer.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 1 to 3 mg daily (management of prostatic carcinoma - the only adult indication given in this SPC)

Route: Oral

Frequency: Daily

Elderly: the recommended adult dose is appropriate. Thromboembolic complications are frequent and patients treated with diethylstilbestrol should be considered for treatment with aspirin - section 4.4 specifies prophylaxis with aspirin 75 mg daily. Diethylstilbestrol stimulates breast tissue in males and breast bud irradiation should be considered/may be offered before treatment. Blood pressure should be monitored at regular intervals and treatment stopped if hypertension develops; treatment should be discontinued if surgery is contemplated or if signs or symptoms of thrombosis develop, because of the significantly increased risk of deep vein thrombosis with high oestrogen activity. Care is needed in cardiac failure, hypertension, diabetes (glucose tolerance may be lowered and insulin or other antidiabetic requirements may increase), epilepsy, migraine, depression, contact lens wearers, cholelithiasis, and in any evidence of renal or hepatic impairment or a history of cholestatic jaundice. Thyroid hormone binding globulin may be increased, complicating interpretation of thyroid function tests. Contains lactose - not for patients with rare hereditary galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption. Paediatric: diethylstilbestrol should not be used in children (carcinogenic potential) - no paediatric dose exists. The US-label record in this bundle is an unrelated homeopathic product ('Household Detox') and was not used.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Children and young adults, because of its carcinogenic potential (use is only justified in the management of malignant disease)
Pregnancy - strongly contraindicated; it is not suitable for pre-menopausal women
Oestrogen-dependent neoplasms, especially of the genital tract
Premenopausal carcinoma of the breast
Endometrial hyperplasia or uterine fibromyomata (fibroids)
Undiagnosed vaginal bleeding
History of herpes gestationis; porphyria
Moderate to severe hypertension
Severe or active liver disease; hyperlipoproteinaemia
Any cardiovascular or cerebrovascular disorder, or a history of thromboembolism or conditions predisposing to it such as sickle cell anaemia, untreated polycythaemia and pulmonary hypertension

Side effects

Thrombosis (including cerebral and coronary artery thrombosis), embolism (4.8% in an advanced prostate cancer study) and hypertension
Breast effects in both sexes - discomfort, tenderness, pain, enlargement and discharge; in men gynaecomastia, testicular atrophy and impotence
Nausea and vomiting (nausea 4.8% in the prostate cancer study)
Sodium and fluid retention; peripheral oedema; congestive cardiac failure and pulmonary oedema reported
Headache and migraine; altered mood; lethargy and transient ischaemic attack
Cholelithiasis and cholestatic jaundice; abnormal liver function tests; decreased glucose tolerance and weight increase

Interactions

Oestrogens may antagonise diuretics and reduce the effect of anti-hypertensives (SPC 4.5)

Clinical monograph

How it works

As an oestrogen-receptor agonist it suppresses the hypothalamic-pituitary-gonadal axis, lowering luteinising hormone and consequently testosterone, depriving androgen-dependent prostate tumour cells of stimulation.

Prescribing in practice

It carries a substantial risk of thromboembolic and cardiovascular events, so cardiovascular risk must be assessed and it is generally avoided where this risk is significant.
Fluid retention, gynaecomastia and hepatic effects are recognised and may limit use.
It is reserved for selected cases under specialist oncology or urology supervision when other options are unsuitable.

Monitoring

Monitor for thromboembolic and cardiovascular events, fluid retention and liver function during treatment.

Counselling the patient

Seek urgent help for chest pain, leg swelling or pain, or sudden breathlessness, which may signal a clot.
Breast tenderness or enlargement can occur with this medicine.

Evidence & guidelines

Diethylstilbestrol's androgen-suppressing effect in prostate cancer is long established, though thromboembolic toxicity has limited its modern role.

Reference: ESMO prostate cancer; NICE NG131; specialist hospital protocols; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways