[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Selective oestrogen receptor degraders (SERDs)](https://durgical.com/en/pharmacology/classes/selective-oestrogen-receptor-degraders/) › Elacestrant

# Elacestrant

## SERDs?

Selective oestrogen receptor degraders (SERDs)

## High alert?

An error with this medicine can cause serious harm: double checks and protocols are used.

## Pregnancy: avoid?

Avoid in pregnancy: effective contraception is used by women and by men with partners who could become pregnant, during treatment and for a short time after; breastfeeding is…

Oral oestrogen receptor antagonist of the SERD group, for advanced ER-positive, HER2-negative breast cancer with an ESR1 mutation after hormone therapy.

Updated Nov 1, 2026

## Quick facts

**Group**
[Selective oestrogen receptor degraders (SERDs)](https://durgical.com/en/pharmacology/classes/selective-oestrogen-receptor-degraders/)

**Target**
Oestrogen receptor alpha (ERα), ligand-binding domain

**Used for**
ER-positive

**Key effects**
Muscle and joint pain · Nausea · Tiredness

**Monitor**
ESR1 mutation test before starting · Liver tests

**ATC**
L02BA04

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

◎**Oestrogen receptor alpha (ERα), ligand-binding domain**Elacestrant

ⓘ The crystal shows elacestrant (code name RAD1901) in the ligand-binding pocket of human ERα.

**Target in 3D:** Oestrogen receptor alpha (ERα), ligand-binding domain. PDB structure 7TE7 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/7TE7) · Drag to rotate · pinch to zoom

Elacestrant binds the oestrogen receptor and stops oestrogen from binding, so oestrogen-dependent breast cancer cells stop growing. It is grouped with fulvestrant as a selective oestrogen receptor degrader, but unlike fulvestrant it is a non-steroidal tablet. Its benefit is clearest in tumours with ESR1 mutations, a common way that breast cancers escape aromatase inhibitors by keeping the receptor active with little oestrogen.

- Elacestrant occupies the oestrogen receptor's ligand pocket
- Oestrogen can no longer bind and switch genes on
- Oestrogen-driven tumour growth stops, even with ESR1 mutations

## Indications

- ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer in postmenopausal women or adult men, after at least one line of endocrine therapy. [Breast cancer →](https://durgical.com/en/conditions/breast-cancer/)

## Adverse effects

### Common

- Muscle and joint pain
- Nausea, vomiting, diarrhoea, constipation, indigestion
- Tiredness, decreased appetite, headache
- Hot flushes
- Raised cholesterol, triglycerides, liver enzymes and creatinine; low sodium

### Serious (rare, important)

- Liver problems: yellow skin or eyes, dark urine, lower abdominal pain

## Contraindications

- No absolute contraindications in the label apart from hypersensitivity; see the warnings

## Key interactions

**St John's wort and other enzyme inducers**
Lower elacestrant levels and may make it less effective.

**Some other prescription medicines**
Must not be combined or need dose changes, so the full medicine list is reviewed before starting.

## What is monitored

- ESR1 mutation test before starting (tumour or blood test)
- Cholesterol and triglycerides
- Liver tests
- Pregnancy test before starting in women who could be pregnant

## Administration and safety

- Oral tablet taken with food at about the same time each day.
- Swallowed whole: not split, chewed or crushed.
- A missed or vomited dose is not doubled; the next dose is taken at the usual time.

## Pregnancy and breastfeeding

Avoid in pregnancy: effective contraception is used by women and by men with partners who could become pregnant, during treatment and for a short time after; breastfeeding is stopped.

## Nursing care

- Check that an ESR1 mutation was confirmed before the first dose.
- Ask about St John's wort and review all medicines and supplements.
- Ask about liver disease or high cholesterol before starting, and follow the lipid and liver results.
- Teach to report yellow skin or eyes, dark urine or abdominal pain.

## Pharmacokinetics

**Absorption**
Oral tablet, taken with food once a day.

**Metabolism**
Its levels are lowered by inducers such as St John's wort, and some medicines should not be combined with it.

## Memory aid

ELAcestrant = the oral SERD for the ESR1-mutant tumour: the receptor that escaped the aromatase inhibitor is now blocked directly.

## Test yourself

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

## Which tumour test selects patients for elacestrant?

An ESR1 mutation test, which can be done on a blood sample.

## How does elacestrant differ from fulvestrant in how it is given?

Elacestrant is an oral tablet; fulvestrant is a slow intramuscular injection.

## Which laboratory changes should be followed on elacestrant?

Cholesterol and triglycerides, liver enzymes, sodium and creatinine.

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

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

## What the labels mean

**High alert**
An error with this medicine can cause serious harm: double checks and protocols are used.

**Pregnancy: avoid**
Avoid in pregnancy: effective contraception is used by women and by men with partners who could become pregnant, during treatment and for a short time after; breastfeeding is…

## Connections

## Related drugs 3

- [Fulvestrant](https://durgical.com/en/pharmacology/fulvestrant/)
- [Letrozole](https://durgical.com/en/pharmacology/letrozole/)
- [Tamoxifen](https://durgical.com/en/pharmacology/tamoxifen/)

## Related conditions 1

- [Breast cancer](https://durgical.com/en/conditions/breast-cancer/)

[← Back to the class: Selective oestrogen receptor degraders (SERDs)](https://durgical.com/en/pharmacology/classes/selective-oestrogen-receptor-degraders/)

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

Sources: [Elacestrant: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a623011.html) (MedlinePlus (U.S. National Library of Medicine), 2023); [FDA approves elacestrant for ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer](https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-elacestrant-er-positive-her2-negative-esr1-mutated-advanced-or-metastatic-breast-cancer) (U.S. Food and Drug Administration, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L02BA04) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); [Estrogen Receptor Alpha Ligand Binding Domain in Complex with RAD1901](https://www.rcsb.org/structure/7TE7) (RCSB Protein Data Bank, 2022).

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Representative model, for educational purposes only.

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