Mechanism of Action of Fulvestrant
Indications of Fulvestrant
- For the treatment of hormone receptor-positive metastatic breast cancer in postmenopausal women with disease progression following anti-estrogen therapy.
- Fulvestrant is a steroidal antiestrogen that is used in the treatment of hormone-receptor-positive metastatic breast cancer. Fulvestranttherapy can be associated with serum enzyme elevations but has yet to be linked to instances of clinically apparent acute liver injury in the published literature.
- Refractory, advanced Breast cancer
- Refractory, metastatic Breast cancer
- It is indicated as monotherapy for the treatment of estrogen receptor positive, locally advanced or metastatic breast cancer in postmenopausal women not previously treated with endocrine therapy, or with disease relapse on or after adjuvant antiestrogen therapy, or disease progression on antiestrogen therapy in combination with palbociclib for the treatment of hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative locally advanced or metastatic breast cancer in women who have received prior endocrine therapy. In pre- or perimenopausal women, the combination treatment with palbociclib should be combined with a luteinizing hormone-releasing hormone (LHRH) agonist.
Contraindications of Fulvestrant
- Low amount of magnesium in the blood
- The high amount of calcium in the blood
- Low amount of potassium in the blood
- Decreased blood platelets
- Decreased white blood cells
- Very rapid heartbeat – torsades de pointes
- Prolonged QT interval on EKG
- Abnormal EKG with QT changes from birth
- Obstruction of a blood vessel by a blood clot
- Overgrowth of the Uterine Lining
- Pregnancy
- A mother who is producing milk and breastfeeding
- Increased risk of bleeding due to a clotting disorder
- Decreased Blood Platelets
- Liver problems
- Pregnancy
- A mother who is producing milk and breastfeeding
- Allergies to Fulvestrant
Dosage of Fulvestrant
Strengths: 50 mg/mL
Breast Cancer
Monotherapy
- 500 mg IM into the buttocks (gluteal area) slowly (1 to 2 minutes per injection) as two 5 mL injections, one in each buttock, on days 1, 15, 29 and once monthly thereafter
Combination Therapy
- In combination with palbociclib or abemaciclib: 500 mg IM into the buttocks (gluteal area) slowly (1 to 2 minutes per injection) as two 5 mL injections, one in each buttock, on days 1, 15, 29 and once monthly thereafter.
Side Effects of Fulvestrant
More Common
- Bloating or swelling of the face, arms, hands, lower legs, or feet
- Difficult or labored breathing
- tightness in the chest
- Back pain
- bladder pain
- bloody or cloudy urine
- body aches or pain
- bone pain
- burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings
- depression
- diarrhea
- difficulty having a bowel movement
- difficulty with moving
- dizziness
- dryness or soreness of the throat
- feeling faint, dizzy, or lightheaded
- feeling of warmth or heat
Common
- are allergic to fulvestrant or any ingredients of the medication
- are breast-feeding
- are pregnant
- headache
- hot flashes
- loss of appetite
- mild pain, redness, or swelling around the site of the injection
- nausea
- rash
- vomiting
- weakness
Drug Interactions of Fulvestrant
Fulvestrant may interact with following drugs, supplements & may change the efficacy of the drug
- celecoxib
- dapsone
- echinacea
- fluoxetine
- ganciclovir
- glipizide
- glyburide
- interferon
- ketamine
- leflunomide
- leucovorin
- levamisole
- live vaccines (e.g., BCG, yellow fever)
- losartan
- montelukast
- nateglinide
- other cancer medications (including but not limited to cytarabine, flucytosine, methotrexate)
- pimecrolimus
- phenytoin
- sulfamethoxazole
- tacrolimus
- tamoxifen
- tolbutamide
- trimethoprim
- voriconazole
- warfarin
Pregnancy Category of Fulvestrant
US FDA pregnancy category: N (Not assigned)
Pregnancy
This medication should not be used during pregnancy. It may cause severe harm to the developing baby if it is used by the mother during childhood. If you become pregnant while taking this medication, contact your doctor immediately.
Lactation
It is not known if fulvestrant passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding. The safety and effectiveness of using this medication have not been established for children.
References
