[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Estrogens](https://durgical.com/en/pharmacology/classes/estrogens/) › Estradiol

# Estradiol

## Estrogens?

Estrogens

## Pregnancy: contraindicated?

Not used in pregnancy; it has no role there and is contraindicated.

The main human estrogen, given by mouth, skin or vagina for menopausal symptoms and estrogen deficiency, with a progestogen if the uterus is present.

Updated Nov 1, 2026

Also called: 17β-estradiol, Estradiol valerate, Estradiol hemihydrate

## Quick facts

**Group**
[Estrogens](https://durgical.com/en/pharmacology/classes/estrogens/)

**Target**
Estrogen receptor α (ERα), a nuclear receptor

**Used for**
Moderate to severe hot flushes

**Key effects**
Breast tenderness · Nausea · Headache

**Monitor**
Need for continued treatment · Blood pressure

**ATC**
G03CA03

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Estrogen receptor α (ERα), a nuclear receptor**Estradiol

ⓘ The figure shows estradiol itself in the ligand-binding domain of human estrogen receptor α.

**Target in 3D:** Estrogen receptor α (ERα), a nuclear receptor. PDB structure 1ERE (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1ERE) · Drag to rotate · pinch to zoom

Estradiol is identical to the main estrogen made by the ovary. It binds estrogen receptors α and β and changes gene expression in the brain, bone, vagina, urinary tract, liver, breast and endometrium. It relieves hot flushes, restores the vaginal epithelium, slows bone resorption and, by negative feedback, lowers the high LH and FSH of menopause. Without a progestogen it stimulates the endometrium.

- Estradiol enters target cells and binds estrogen receptors
- The receptor-hormone complex switches estrogen-responsive genes
- Hot flushes ease, the vaginal epithelium and bone are preserved
- LH and FSH fall through negative feedback

## Indications

- Moderate to severe hot flushes of menopause [Menopause and climacteric syndrome →](https://durgical.com/en/conditions/menopause-and-climacteric-syndrome/)
- Vulvovaginal atrophy of menopause (vaginal products preferred when isolated) [Genitourinary syndrome of menopause (atrophic vaginitis) →](https://durgical.com/en/conditions/genitourinary-syndrome-of-menopause/)
- Prevention of postmenopausal osteoporosis when non-estrogen drugs are unsuitable [Osteoporosis →](https://durgical.com/en/conditions/osteoporosis/)
- Hypoestrogenism from hypogonadism or primary ovarian insufficiency [Primary ovarian insufficiency →](https://durgical.com/en/conditions/primary-ovarian-insufficiency/)
- Palliation of some advanced prostate and breast cancers [Prostate cancer →](https://durgical.com/en/conditions/prostate-cancer/)

## Adverse effects

### Common

- Breast tenderness
- Nausea, bloating
- Headache
- Vaginal bleeding or spotting
- Leg cramps, fluid retention

### Serious (rare, important)

- Endometrial hyperplasia and cancer when given without a progestogen
- Stroke and deep vein thrombosis; pulmonary embolism and heart attack with a progestin
- Breast cancer (with a progestin) and possibly ovarian cancer
- Probable dementia in women over 65
- Gallbladder disease, pancreatitis from high triglycerides, retinal thrombosis

## Contraindications

- Undiagnosed abnormal genital bleeding
- Current or past breast cancer, or estrogen-dependent neoplasia
- Active or past DVT, pulmonary embolism, stroke or heart attack
- Liver impairment or disease
- Protein C, protein S or antithrombin deficiency or other thrombophilia
- Pregnancy

## Key interactions

**CYP3A4 inducers (St John's wort, phenobarbital, carbamazepine, rifampicin)**
Lower estrogen levels and less effect

**CYP3A4 inhibitors (some macrolides, azole antifungals, ritonavir, grapefruit juice)**
Higher estrogen levels and more side effects

**Levothyroxine**
Higher thyroid-binding globulin; the thyroid dose may need to rise

## What is monitored

- Need for continued treatment, reviewed periodically
- Blood pressure
- Breast examination and mammography
- Any abnormal vaginal bleeding (endometrial evaluation)
- Triglycerides and TSH in women on thyroid hormone

## Administration and safety

- Oral, transdermal and vaginal forms exist; the route is as ordered and products are not interchanged without an order
- Patches are applied to clean, dry skin and the site is rotated
- Used at the lowest effective dose for the shortest time
- Stopped, when possible, several weeks before surgery with a high risk of thrombosis or during long immobilisation

## Pregnancy and breastfeeding

Not used in pregnancy; it has no role there and is contraindicated.

## Nursing care

- Teach warning signs: leg pain or swelling, chest pain, sudden breathlessness, facial droop or weakness, sudden vision change or severe headache
- Teach to report any vaginal bleeding and breast lumps
- Encourage stopping smoking, which adds to the risk of clots and stroke
- Ask about thyroid medication
- Remind that a woman with a uterus also needs a progestogen

## Pharmacokinetics

**Absorption**
By mouth (with first-pass liver metabolism), through the skin as patches or gel, or in the vagina

**Distribution**
Bound to SHBG and albumin in plasma

**Metabolism**
In the liver, partly by CYP3A4, with enterohepatic recirculation

**Elimination**
As conjugated metabolites in urine

## Memory aid

Estradiol = «E2, lowest and shortest»: E for Endometrium needs a progestin, 2 for the two clot risks (DVT and stroke).

## Test yourself

Think of the answer, then tap the question to see it.

## Which women taking estradiol also need a progestogen?

Women who still have a uterus, to prevent endometrial hyperplasia and cancer.

## Which two cardiovascular risks did estrogen alone raise in the Women's Health Initiative?

Stroke and deep vein thrombosis (it also raised probable dementia in women over 65).

## Why is estradiol stopped before major surgery when possible?

It increases the risk of venous thromboembolism, which surgery and immobilisation also raise.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/estradiol/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**Pregnancy: contraindicated**
Not used in pregnancy; it has no role there and is contraindicated.

## Connections

## Related drugs 4

- [Conjugated estrogens](https://durgical.com/en/pharmacology/conjugated-estrogens/)
- [Progesterone](https://durgical.com/en/pharmacology/progesterone/)
- [Norethisterone](https://durgical.com/en/pharmacology/norethisterone/)
- [Raloxifene](https://durgical.com/en/pharmacology/raloxifene/)

## Related conditions 5

- [Menopause and climacteric syndrome](https://durgical.com/en/conditions/menopause-and-climacteric-syndrome/)
- [Genitourinary syndrome of menopause (atrophic vaginitis)](https://durgical.com/en/conditions/genitourinary-syndrome-of-menopause/)
- [Osteoporosis](https://durgical.com/en/conditions/osteoporosis/)
- [Primary ovarian insufficiency](https://durgical.com/en/conditions/primary-ovarian-insufficiency/)
- [Prostate cancer](https://durgical.com/en/conditions/prostate-cancer/)

[← Back to the class: Estrogens](https://durgical.com/en/pharmacology/classes/estrogens/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - ESTRADIOL AND NORETHINDRONE ACETATE tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=50c786d6-91bd-4eea-9455-ff2abc08372f) (DailyMed (U.S. National Library of Medicine), 2026); [Estrogen: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682922.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=G03CA03) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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