Fulvestrant® Injection for HR-Positive Metastatic Breast Cancer

What Fulvestrant® Is and How It Works

Fulvestrant is a selective estrogen receptor degrader (SERD) used in hormone receptor–positive advanced breast cancer. If you compare fulvestrant injection price options, Canadian pharmacy pricing can help lower overall treatment costs. YouDrugstore is a licensed Canadian pharmacy headquartered in Manitoba, where licensed pharmacists review prescriptions before dispensing. Define fulvestrant in clinical terms: it binds to estrogen receptors, blocks signaling, and speeds receptor degradation, which slows or stops tumor growth in estrogen-driven disease.

Indications include postmenopausal women, and some men, with hormone receptor–positive, HER2‑negative advanced or metastatic breast cancer. It can be used alone after progression on prior endocrine therapy or with a CDK4/6 inhibitor. Common combination regimens include fulvestrant plus palbociclib, abemaciclib plus fulvestrant, or ribociclib plus fulvestrant. As injectable endocrine therapy, it is given intramuscularly by a healthcare professional. To learn more about clinical use, see Fulvestrant Injection Hormone Therapy For Breast Cancer.

We work with licensed, vetted international partner pharmacies to supply authentic brand medications and a wide range of generics at affordable prices.

Dosage and Usage

• Standard schedule: 500 mg on Day 1, Day 15, and Day 29, then every 28 days thereafter.
• Fulvestrant injection 250mg: the 500 mg dose is administered as two separate 250 mg (5 mL) intramuscular injections, one in each buttock.
• Administration: slow, deep gluteal intramuscular injection over 1–2 minutes per syringe by trained staff.
• Injection technique: alternate buttocks; inject into the upper outer quadrant to reduce sciatic nerve risk.
• Do not mix fulvestrant with other drugs in the same syringe and do not administer intravenously.
• Missed dose: give as soon as feasible; maintain the monthly cycle as directed by the prescriber.
• Hepatic impairment: dose adjustments may be required in moderate impairment; the prescriber will determine the plan.
• Drug interactions: combinations with CDK4/6 inhibitors are common; monitor for additive toxicities per the regimen’s label.
• Fulvestrant injection uses include monotherapy after prior aromatase inhibitor therapy and in combination after progression on earlier endocrine therapy.
• Fulvestrant injection site reactions can occur; rotate sides and follow proper technique to limit discomfort.

• Refrigerate prefilled syringes at 2–8 °C (36–46 °F). Do not freeze.
• Keep in original packaging to protect from light.
• If transport is needed, use an insulated container with cold packs to keep 2–8 °C. Do not place syringes directly on ice.
• Allow syringes to reach room temperature before administration, as directed by clinic protocol.
• Avoid heat, sunlight, and shaking during travel.
• When you order, we use prompt, express, cold-chain shipping.

Benefits and Savings

Fulvestrant endocrine therapy provides complete estrogen receptor antagonism and receptor degradation without the partial agonist effects seen with older agents. In trials, fulvestrant 500 mg achieved meaningful progression-free survival as monotherapy and further gains when combined with CDK4/6 inhibitors. Many find the once-monthly maintenance schedule convenient after loading doses.

Patients often compare fulvestrant cost before starting or continuing therapy. US customers typically see 60–80% savings versus common US cash prices when ordering from a licensed Canadian pharmacy. If comparing brand and generic options, some also review Faslodex price to understand potential differences. Multi-month quantities can reduce the per‑month price, and you can set gentle reorder reminders so refills arrive in time for scheduled clinic visits.

We carry both brand and select generics when available, including options from recognized manufacturers such as Sandoz fulvestrant where supplied.

Side Effects and Safety

• Injection site pain, swelling, or bruising
• Nausea, vomiting, diarrhea, or constipation
• Hot flashes and sweats
• Headache, fatigue, or dizziness
• Back pain, arthralgia, or bone pain
• Loss of appetite or mild weight change
• Elevated liver enzymes on blood tests

Serious effects are uncommon but can include allergic reactions, significant liver injury, neuropathy due to injection placement, and bleeding, especially in those with thrombocytopenia or on anticoagulants. Fulvestrant can harm a developing fetus and is not recommended during pregnancy or breastfeeding. Use effective contraception during treatment and for a period after, as advised by the prescriber.

Onset Time

Fulvestrant binds and degrades estrogen receptors quickly, but clinical results take time. Symptom stabilization may begin within several weeks as loading doses complete. Objective responses and tumor shrinkage, when they occur, are often evaluated over 8–12 weeks using imaging and clinical assessment. In combination regimens, improvements in progression-free survival typically emerge over the first few months as dosing stabilizes.

Compare With Alternatives

For first‑line endocrine therapy in postmenopausal women, aromatase inhibitors are common choices. Anastrozole lowers estrogen production and is taken orally once daily. In some studies, fulvestrant 500 mg showed longer progression-free survival than anastrozole in select patients, but choice depends on prior therapy and tumor biology.

CDK4/6 inhibitors add targeted cell‑cycle control. Adding palbociclib to fulvestrant significantly prolonged progression‑free survival versus fulvestrant alone in previously treated patients. If considering this path, see details on Ibrance® and discuss eligibility with the oncology team. Similar benefits were observed with abemaciclib and ribociclib combinations.

Other targeted agents may be used based on tumor markers. For example, elacestrant is an oral SERD used in ESR1‑mutated disease after prior endocrine therapy. For HER2‑positive metastatic cancer, endocrine therapies are often combined with anti‑HER2 agents rather than used alone.

Combination Therapy

• Palbociclib plus fulvestrant: improves progression‑free survival after prior endocrine therapy; monitor for neutropenia.
• Abemaciclib plus fulvestrant (Verzenio fulvestrant): may increase gastrointestinal effects; dose adjustments can manage diarrhea.
• Ribociclib plus fulvestrant: monitor QT interval and liver tests.
• Ovarian suppression for premenopausal patients: add an LHRH agonist to make the endocrine environment postmenopausal.
• Alpelisib with endocrine therapy in PIK3CA‑mutated tumors; monitor glucose and rash.
• Bone‑targeted therapy (denosumab or zoledronic acid) for skeletal health in metastatic bone disease.

Patient Suitability and Cost-Saving Tips

Candidates include adults with hormone receptor–positive, HER2‑negative advanced or metastatic breast cancer after progression on prior endocrine therapy, or those starting combination therapy with a CDK4/6 inhibitor. It is generally not used as monotherapy for premenopausal patients without concurrent ovarian suppression. Severe hepatic impairment may limit use or require adjustment.

Those with bleeding risks or on anticoagulants may have higher injection site bleeding or bruising. Hypersensitivity to fulvestrant or any component of the injection is a contraindication. Fulvestrant is not recommended during pregnancy or breastfeeding; use reliable contraception during therapy and for a time after. Discuss the plan for treatment after Faslodex if disease progresses, including other endocrine agents or targeted options based on tumor profiling.

To manage fulvestrant price, consider ordering multi‑month supplies when your clinic schedule is stable. That can lower monthly costs and reduce the number of shipments. You can turn on reorder reminders so you have doses ready for Day 1, Day 15, and monthly maintenance visits. If you need cost comparisons, request a quote for fulvestrant injection cost alongside any planned combination medicines.

Authoritative Sources

AstraZeneca Faslodex (fulvestrant) Patient and HCP Information

Health Canada Drug Product Database: Fulvestrant

FDA Drugs@FDA: Faslodex (fulvestrant) Prescribing Information

Order Fulvestrant® from YouDrugstore: add to cart, upload your prescription, and we ship with prompt, express, cold-chain handling.

This content is educational and does not replace advice from your healthcare professional. Always follow your oncology team’s instructions for diagnosis, treatment, and monitoring.