Fulvestrant
Fulvestrant is a selective estrogen receptor degrader (SERD) used to treat hormone receptor-positive breast cancer in postmenopausal women. It works by binding competitively to estrogen receptors, blocking the effects of estrogen that can promote cancer growth, and causing downregulation of the receptor. This medication is typically used when cancer has progressed after other anti-estrogen therapies.
Fulvestrant is an estrogen receptor antagonist used to treat hormone receptor-positive breast cancer by blocking estrogen from stimulating tumor growth.
Key facts at a glance
- ATC
- L02BA03
- RxNorm
- 282357
- Generic
- Fulvestrant
- Class
- atc-l02
- Brands
- Faslodex, Cligavyx
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- prefilled syringe
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg once monthly (after initial loading dose)
- Maximum
- consult physician
- Frequency
- once monthly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 500mg on days 0, 14, 28, then monthly
- Maximum
- consult physician
- Frequency
- loading dose then monthly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 500mg once monthly (no dose adjustment required)
- Maximum
- consult physician
- Frequency
- once monthly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteravoid use
Fulvestrant should not be used during pregnancy unless clearly necessary. Women of childbearing potential should use effective contraception during treatment and for 2 years after the last dose.
regular fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second trimesteravoid use
Discontinue fulvestrant if pregnancy occurs and advise patient on potential risks to fetus
regular fetal monitoring and ultrasound assessments
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
third trimesteravoid use
Not recommended during third trimester; consider alternative therapies for breast cancer during pregnancy
regular fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedingdiscontinue breastfeeding
It is unknown if fulvestrant is excreted in human breast milk. Breastfeeding should be discontinued during treatment and for 2 years after the last dose due to potential harm to the infant.
no specific monitoring required
Use of this medication in this population requires careful consideration of risks and benefits.
pediatric_age
children adolescentsnot established
Fulvestrant is not indicated for use in pediatric patients. Safety and efficacy have not been established in children or adolescents.
not applicable
geriatric
elderly 65 plusno dose adjustment required
No dose adjustment is required for patients over 65 years. However, elderly patients may have increased sensitivity to the drug and should be monitored closely for adverse effects.
regular assessment of tolerability and adverse effects
Use with caution and monitor for adverse effects.
renal_impairment
mild moderateno dose adjustment required
No dose adjustment is required for patients with mild to moderate renal impairment (CrCl 30-80 mL/min). Use with caution in patients with severe renal impairment.
monitor renal function periodically
Use with caution and monitor for adverse effects.
hepatic_impairment
mild moderateconsider dose reduction
Fulvestrant is metabolized in the liver. For patients with mild to moderate hepatic impairment, no specific dose adjustment is required, but close monitoring is recommended. Use with caution.
monitor liver function tests regularly
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA approval year
General prescribing information
Drug class
Drug class information
Common uses
Common therapeutic uses
Mechanism of action
Pharmacological mechanism
Treatment of hormone receptor-positive metastatic breast cancer in postmenopausal women with disease progression following anti-estrogen therapy. May be used alone or in combination with other targeted therapies.
Fulvestrant is a selective estrogen receptor degrader (SERD) that competitively binds to estrogen receptors with affinity comparable to estradiol. By binding to these receptors, it prevents estrogen from activating them, leading to receptor downregulation and inhibition of estrogen-dependent tumor growth.
Administered as intramuscular injections (typically 500mg on days 0, 14, and then monthly). Common side effects may include injection site pain, nausea, and hot flashes. Requires proper handling and administration by healthcare professionals. May increase risk of bleeding in patients taking anticoagulants.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy