Dosing & Uses
Dosage Forms & Strengths
injectable solution
- 250mg/5mL
Advanced Breast Cancer
Also see Administration
Monotherapy
- Indicated for hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative in postmenopausal women not previously treated with endocrine therapy
- Indicated for HR-positive in postmenopausal women with disease progression following endocrine therapy
- 500 mg IM on days 1, 15, 29, then once monthly thereafter
Combination therapy with palbociclib or abemaciclib
- Indicated HR-positive, HER2-negative advanced or metastatic breast cancer in women with disease progression after endocrine therapy
- Fulvestrant 500 mg IM on days 1, 15, 29, and once monthly thereafter AND
- Palbociclib 125 mg PO qDay for days 1-21 of each 28-day cycle OR
- Abemaciclib 150 mg PO BID
- Continue until disease progression or unacceptable toxicity
- Pre/perimenopausal women treated with the palbociclib/abemaciclib combination should be treated with luteinizing hormone-releasing hormone (LHRH) agonists according to current clinical practice standards
Combination with ribociclib
- Indicated HR-positive, HER2-negative advanced or metastatic breast cancer in postmenopausal women in combination with ribociclib
- Administer as initial endocrine based therapy or following disease progression on endocrine therapy
- Fulvestrant 500 mg IM on days 1, 15, 29, and once monthly thereafter AND
- Ribociclib 600 mg for days 1-21 of each 28-day cycle
- Continue until disease progression or unacceptable toxicity
- Pre/perimenopausal women treated with the ribociclib combination should be treated with luteinizing hormone-releasing hormone (LHRH) agonists according to current clinical practice standards
Dosage Modifications
Hepatic impairment
- Mild (Child-Pugh A): No dosage adjustment required
- Moderate (Child-Pugh B): 250 mg IM on days 1, 15, 29, then once monthly thereafter
- Severe (Child-Pugh C): Not studied
Renal impairment
- Negligible amounts of fulvestrant are eliminated in urine
- In clinical trials, fulvestrant concentrations in women with eCrCl ≥30 mL/min were similar to women with normal creatinine
Dosage Forms & Strengths
injectable solution
- 50mg/mL
Precocious Puberty (Off-label)
Indicated in females for progressive precocious puberty associated with McCune-Albright syndrome
Hepatic Impairment
- Dose adjustment may be required, although no specific recommendations defined for children with hepatic impairment (in adults with Child-Pugh class B, the dose is decreased by 50%)
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (0)
Serious - Use Alternative (1)
- etrasimod
etrasimod, fulvestrant. Either increases effects of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug. Risk of additive immune system effects with etrasimod has not been studied in combination with antineoplastic, immune-modulating, or noncorticosteroid immunosuppressive therapies. Avoid coadministration during and in the weeks following administration of etrasimod.
Monitor Closely (1)
- siponimod
siponimod and fulvestrant both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Caution if coadministered because of additive immunosuppressive effects during such therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, consider the half-life and mode of action of these drugs to avoid unintended additive immunosuppressive effects.
Minor (2)
- maitake
maitake increases effects of fulvestrant by pharmacodynamic synergism. Minor/Significance Unknown. Maitake mushroom has anti-tumor effects (animal/in vitro research).
- taurine
fulvestrant decreases levels of taurine by unspecified interaction mechanism. Minor/Significance Unknown.
Adverse Effects
>10%
Nausea (26%)
Asthenia (23%)
Pain (19%)
Vasodilatation (18%)
Pharyngitis (16%)
HA (15%)
Back pain (14%)
Constipation (13%)
Vomiting (13%)
Abd pain (12%)
Diarrhea (12%)
Inj site pain (11%)
1-10%
Cough (10%)
Anorexia (9%)
Peripheral edema (9%)
Chest pain (7%)
Flu-like syndrome (7%)
Rash (7%)
Depression (6%)
Fever (6%)
UTI (6%)
Anemia (5%)
<1%
Angioedema
Leukopenia
Myalgia
Thrombosis
Osteoporosis
Postmarketing Reports
Injection site reaction
Thromboembolic phenomena
Myalgia
Vertigo
Leukopenia
Hypersensitivity reactions including angioedema and urticaria
Vaginal bleeding (mainly during the first 6 weeks after changing from existing hormonal therapy)
Elevated bilirubin, gamma GT, hepatitis, and liver failure
Combination Therapy with Palbociclib
Frequency Not Defined
- Neutropenia
- Leukopenia
- Infections
- Fatigue
- Nausea
- Anemia
- Stomatitis
- Diarrhea
- Thrombocytopenia
- Vomiting
- Alopecia
- Rash
- Decreased appetite
- Pyrexia
<10%
- Asthenia (7.5%)
- Aspartate aminotransferase increased (7.5%)
- Dysgeusia (6.7%)
- Epistaxis (6.7%)
- Lacrimation increased (6.4%)
- Dry skin (6.1%)
- Alanine aminotransferase increased (5.8%)
- Vision blurred (5.8%)
- Dry eye (3.8%)
- Febrile neutropenia (0.9%)
Warnings
Contraindications
Hypersensitivity to fulvestrant or any component of formulation
Cautions
Caution in bleeding diathesis, thrombocytopenia, therapeutic anticoagulation
Systemic exposure was increased in patients with moderate hepatic impairment (see Dosage Modifications)
Advise females of reproductive potential of the potential risk to a fetus and to use effective contraception; see Pregnancy section
Therapy can interfere with estradiol measurement by immunoassay, resulting in falsely elevated estradiol levels
Injection site related events including sciatica, neuralgia, neuropathic pain, and peripheral neuropathy reported; caution should be taken while administering therapy at dorsogluteal injection site due to proximity of underlying sciatic nerve
Pregnancy & Lactation
Pregnancy
Based on findings from animal studies and its mechanism of action, fulvestrant can cause fetal harm when administered to a pregnant woman
In animal reproduction studies, administration of fulvestrant to pregnant rats and rabbits during organogenesis resulted in embryo-fetal toxicity at daily doses that are significantly less than the maximum recommended human dose
Advise pregnant women of the potential risk to a fetus
Advise females of reproductive potential to use effective contraception during treatment and for 1 year after the last dose
Pregnancy testing is recommended for females of reproductive potential within 7 days prior to initiating fulvestrant
Lactation
Excretion in human milk unknown
Detected in rat milk
Because of the potential for serious adverse reactions in breastfed infants, advise lactating women not to breastfeed during treatment and for 1 year after the final dose
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Breast cancer: Competitively binds to estrogen receptors on tumors and other tissue targets, producing nuclear complex that decreases DNA synthesis and inhibits estrogen effects; no estrogen-receptor agonist activity; downregulates estrogen receptors and inhibits breast tumor growth
Precocious puberty (off-label): Estrogen receptor antagonist
Absorption
Peak Plasma Time: 7 days
Duration: Plasma levels detected for 1 month
Distribution
Protein Bound: 99%
Vd: 3-5 L/kg
Metabolism
Via multiple hepatic pathways
Excretion
Half-Life: 40 days
Excretion: Feces >90%; urine <1%
Administration
IM Administration
Also see Dosage Modifications
Administer IM in buttocks slowly over 1-2 minutes; not to exceed 250 mg/5 mL per IM injection site
Discard the empty single use syringe into an approved sharps collector in accordance with applicable regulations and institutional policy
Storage
Store in refrigerator at 2-8°C (36-46°F)
Protect from light, store in the original carton until time of use
Images
BRAND | FORM. | UNIT PRICE | PILL IMAGE |
---|---|---|---|
fulvestrant intramuscular - | 250 mg/5 mL solution | ![]() | |
fulvestrant intramuscular - | 250 mg/5 mL solution | ![]() | |
fulvestrant intramuscular - | 250 mg/5 mL solution | ![]() | |
fulvestrant intramuscular - | 250 mg/5 mL solution | ![]() | |
Faslodex intramuscular - | 250 mg/5 mL solution | ![]() |
Copyright © 2010 First DataBank, Inc.
Patient Handout
fulvestrant intramuscular
FULVESTRANT - INJECTION
(ful-VES-trant)
COMMON BRAND NAME(S): Faslodex
USES: Fulvestrant is used to treat certain types of breast cancer. Breast cancer cells need the hormone estrogen in order to grow. Fulvestrant works by blocking the effect of estrogen, slowing tumor cell growth.
HOW TO USE: Read the Patient Information Leaflet if available from your pharmacist before you start using fulvestrant and each time you get a refill. If you have any questions, ask your doctor or pharmacist.This medication is given by slow injection into the buttock muscle by a health care professional. It is given as directed by your doctor, usually every 2 weeks for the first 3 doses and then monthly. The dosage is based on your medical condition.
SIDE EFFECTS: Pain/swelling/redness at the injection site, nausea/vomiting, loss of appetite, constipation, diarrhea, upset stomach, dizziness, tiredness, headache, hot flashes, or trouble sleeping may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: numbness/tingling of arms/legs, back/leg pain, bone/joint pain, mental/mood changes (such as anxiety, depression), shortness of breath, cough that doesn't go away, burning/painful/frequent urination, unusual tiredness, signs of infection (such as sore throat that doesn't go away, fever, chills).A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Before using this medication, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as benzyl alcohol), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, bleeding problems, low platelet counts (thrombocytopenia).This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using fulvestrant. Fulvestrant may harm an unborn baby. Your doctor should order a pregnancy test within 7 days of starting this medication. Ask about reliable forms of non-hormonal birth control (such as condoms, diaphragm with spermicide) while using this medication and for 1 year after the last dose. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this drug and for 1 year after the last dose. Consult your doctor before breastfeeding.
DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.This medication may interfere with certain lab tests (such as estradiol levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
NOTES: Lab and/or medical tests (such as liver function) should be done while you are using this medication. Keep all medical and lab appointments. Consult your doctor for more details.
MISSED DOSE: It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.
STORAGE: Not applicable. This medication is given in a clinic or doctor's office and will not be stored at home.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised November 2023. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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