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 BRAND NAMES
 MECHANISM OF ACTION
Fulvestrant is an estrogen receptor antagonist.
Many breast cancers have estrogen receptors (ER) and the growth of these tumors can be stimulated by estrogen. Fulvestrant binds to the estrogen receptor in a competitive manner with affinity comparable to that of estradiol that is, 10-fold higher than Tamoxifen. After interaction, there is degradation of the receptor, differently from Tamoxifen. This implies that there is reduction in receptor number in human breast cancer cells.
Fulvestrant is well tolerated and has an efficacy similar to aromatase inhibitors.
Treatment of hormone receptor positive metastatic breast cancer in postmenopausal women with disease progression following antiestrogen therapy.
Fulvestrant 500 mg should be administered intramuscularly into the buttocks slowly (1 - 2 minutes per injection) as two 5 mL injections, one in each buttock, on days 1, 15, 29 and once monthly thereafter.
A dose of 250 mg is recommended in patients with moderate hepatic impairment to be administered intramuscularly into the buttock slowly (1 - 2 minutes) as one 5 mL injection on days 1, 15, 29 and once monthly thereafter.
Hypersensitivity to Fulvestrant
 WARNINGS AND PRECAUTIONS
- Blood Disorders: Should be used with caution in patients with bleeding diatheses, thrombocytopenia, or anticoagulant use.
- Hepatic Impairment: A 250 mg dose is recommended in patients with moderate hepatic impairment.
- Pregnancy: Fetal harm can occur when administered to a pregnant woman. Women should be advised of the potential hazard to the fetus and to avoid becoming pregnant while receiving Fulvestrant.
There are no known drug-drug interactions
 PREGNANCY AND LACTATION
- Pregnancy Category D (US). Fulvestrant can cause fetal harm when administered to a pregnant woman.
- Nursing Mothers: discontinue drug or nursing taking into account the importance of drug to the mother.
 SIDE EFFECTS
The most common, clinically significant adverse reactions occurring in ≥ 5% of patients receiving Fulvestrant 500 mg were: injection site pain, nausea, bone pain, arthralgia, headache, back pain, fatigue, pain in extremity, hot flash, vomiting, anorexia, asthenia, musculoskeletal pain, cough, dyspnea, and constipation.
Increased hepatic enzymes (ALT, AST, ALP) occurred in >15% of Fulvestrant patients and were not dose-dependent.