Fulvestrant

Generic Name

Fulvestrant

Other Names

• Faslodex

Drug Class

• Estrogen receptor antagonist

Chemical Formula

C32H47F5O3S

Molecular Weight

606.77 g/mol

Mechanism of Action

• Competitive inhibition of estrogen binding to the estrogen receptor and downregulation of the estrogen receptor protein in target tissues.

Indications

• Treatment of hormone receptor-positive metastatic breast cancer in postmenopausal women.

Common Dosage Forms

• Injection

Typical Dosage

• 250 mg administered intramuscularly on days 1, 15, 29, and once monthly thereafter.

Pediatric Dosage

• Not recommended for use in children.

Geriatric Dosage

• No specific dosage adjustments are recommended in the elderly population.

Side Effects

• Injection site reactions, hot flashes, asthenia, nausea, musculoskeletal pain, headache, back pain, fatigue, and others.

Contraindications

• Hypersensitivity to the drug

Pregnancy Category

• D - Do not use in pregnancy

Lactation Safety

• Not recommended during lactation

Drug Interactions

• Strong CYP3A4 inhibitors may increase fulvestrant exposure

Overdose Symptoms

• No specific symptoms reported

Antidote for Overdose

• No specific antidote, manage with supportive care

Storage Conditions

• Store at controlled room temperature (20-25°C). Protect from light.

Pharmacokinetics

• Absorption: Well absorbed after intramuscular injection
• Distribution: Highly protein-bound
• Metabolism: Undergoes extensive hepatic metabolism via CYP3A4
• Excretion: Primarily eliminated in feces

Precautions

• Monitor liver function tests periodically during treatment.

Warnings

• May cause fetal harm if used during pregnancy.

Others

• Regular monitoring of hormonal markers recommended during treatment.