Fulvestrant is a prescription injection used to treat certain hormone receptor-positive conditions. Understanding how to use it correctly is important for effective treatment. This article provides clear instructions, key precautions, and common concerns to help patients follow their therapy with confidence.

Instructions for use of Fulvestrant

1. Indications for Fulvestrant

(1) It is suitable for patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer who have not received endocrine therapy after menopause.

(2) It is suitable for postmenopausal patients with advanced hormone receptor (HR)-positive breast cancer whose disease has progressed after endocrine therapy.

(3) In combination with Riboxil, it is suitable for postmenopausal patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer.

(4) In combination with palbociclib or abemaciclib, it is suitable for patients with hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer.

2. Recommended dose

(1) Single drug: The recommended dose of Fulvestrant is 500 mg, generally injected intramuscularly into the buttocks twice on the 1st, 15th and 29th days (each time slowly injected for 1-2 minutes), 5 ml each time, and then once a month.

(2) Combination drug use: When used in combination with ribociclib, abemaciclib and palbociclib, the recommended dose is generally 500 mg, generally injected intramuscularly into the buttocks twice on the 1st, 15th and 29th days (each time slowly injected for 1-2 minutes), 5 ml each time, and then once a month.

3. Dose adjustment

The recommended initial dose for patients with moderate liver impairment is generally 250 mg, which is usually injected intramuscularly in the buttocks once on the 1st, 15th and 29th days (each time slowly injected for 1-2 minutes), 5 ml each time, and then once a month.

4. Precautions for Fulvestrant

(1) Risk of bleeding

This product is administered by intramuscular injection, so patients with bleeding disorders, thrombocytopenia or those receiving anticoagulant therapy should use this product with caution.

(2) Aggravation of liver impairment

This product should be used with caution in patients with mild to moderate liver impairment.

(3) Injection site reactions

Sciatica, neuropathic pain and peripheral neuropathy may occur, so be careful when injecting.

(4) Embryo-fetal toxicity

Inform pregnant women of the potential risks to the fetus and recommend that pregnant women take contraceptive measures during treatment and within one year after the last dose.

(5) Impact on estradiol antibody determination

Since estradiol and Fulvestrant have similar structures, they may interfere with the accuracy of the values and lead to a false increase in estradiol antibodies.