Faslodex Explained: How Fulvestrant Works in Advanced Breast Cancer Treatment

什么是 Fulvestrant？

Fulvestrant (pronounced [fool VES trant]) is also known by the brand name, Faslodex. It is an antineoplastic (anticancer) drug that belongs to a class called estrogen receptor antagonists. It is an injectable solution that is used to treat locally advanced or metastatic breast cancer in postmenopausal, 雌激素受体阳性的女性. Fulvestrant is a form of endocrine (hormonal) therapy known as a selective estrogen receptor degrader (SERD). It is not considered traditional cytotoxic 化疗.

What Is Endocrine (Hormonal) Therapy?

Endocrine therapy is a cancer treatment used for tumors that depend on hormones such as estrogen to grow. Instead of directly killing rapidly dividing cells like cytotoxic chemotherapy, endocrine therapies work by blocking hormone signaling or lowering hormone effects in the body. Fulvestrant works by binding to the estrogen receptor and promoting its degradation, which helps slow or stop the growth of estrogen receptor–positive breast cancer.

What Is Endocrine (Hormonal) Therapy?

Endocrine therapy is a cancer treatment used for tumors that depend on hormones such as estrogen to grow. Instead of directly killing rapidly dividing cells like cytotoxic chemotherapy, endocrine therapies work by blocking hormone signaling or lowering hormone effects in the body. Fulvestrant works by binding to the estrogen receptor and promoting its degradation, which helps slow or stop the growth of estrogen receptor–positive breast cancer.

Safe Handling Precautions

Fulvestrant is considered a hazardous medication; therefore, it is important to take appropriate precautions for receiving, handling, storing, administering, and disposing of this medication. It is recommended to wear gloves when handling or administering this medication and to keep it stored in its original container.

Fulvestrant 如何使用？

Fulvestrant has been approved by the Food and Drug Administration (FDA) to treat certain types of breast cancer. It may be used alone or in combination with other anticancer therapies, such as CDK4/6 inhibitors (for example, palbociclib [Ibrance], abemaciclib [Verzenio], or ribociclib [Kisqali]), depending on the cancer’s characteristics and prior treatment history. When used in appropriate patients, combination therapy can improve outcomes such as delaying cancer progression.

可用配方

Fulvestrant is only available in the form of an injection to be administered intramuscularly in the buttocks (gluteal) area. Each pre-filled syringe is available as a 5 ml dose, which contains 250 mg of fulvestrant. Therefore, each ml contains 50 mg of fulvestrant. Other ingredients included in the injection are ethanol (96%), 苯甲醇 （100 毫克/毫升）、苯甲酸苄酯和精制蓖麻油。

使用方法

Fulvestrant 可与食物同时服用。预充式氟维司群注射器仅供臀部肌肉注射。切勿静脉注射、皮下注射或动脉注射。应使用两支预充式注射器（每 5 毫升含 250 毫克），每侧臀部各一支，每次注射需缓慢进行 1 至 2 分钟。每侧臀部注射量不得超过 5 毫升。

To prepare each syringe for administration, hold the syringe upright, carefully tilt the syringe cap back and forth (without twisting) until the cap disconnects for removal. Pull the cap off by pulling up without touching the syringe tip (to maintain sterility), attach the safety needle to the syringe tip, and twist firmly to lock. Remove the needle cap by pulling straight off to avoid damaging the needle point, remove the needle sheath, and expel excess air from the syringe before administration. Refer to the product labeling for more detailed instructions.

Fulvestrant 初始剂量为 500 毫克，分别在第 1、15 和 29 天给药，之后每 4 周服用 500 毫克，以维持治疗。具体剂量取决于癌症类型和严重程度。请咨询您的医生，确认正确的剂量和给药频率。剂量不应超过或低于处方剂量。

漏服剂量

如果您漏服此药，请立即联系您的医生，因为此药需要规律服药。请勿尝试加倍剂量来弥补。

贮存

Keep medication stored in the original carton. Do not freeze and keep protected from light. Storage requirements may vary by product. Refer to the manufacturer’s labeling for further details. Fulvestrant should be stored in the refrigerator; however, some variations of fulvestrant can be stored at either room temperature or in the refrigerator. To minimize discomfort, you can take the medication out of the refrigerator up to 1 hour before the scheduled dose and allow it to reach room temperature. Do not reuse any single-use syringes and discard any unused portion. Dispose of the product as directed; do not flush down the drain.

What To Avoid While Taking Fulvestrant

While receiving fulvestrant, you must follow some precautions. Always tell your physician about any medication you are already taking. Do not start or stop any prescription, over-the-counter (OTC), vitamin, or herbal product without prior consent from your physician or pharmacist, as they may have some significant interactions with fulvestrant.

怀孕和Fulvestrant

Pregnancy status must be checked within 7 days prior to starting treatment in women of childbearing age. Effective contraception must be used during treatment and for 1 year after the last dose. Fulvestrant may cause fetal harm and is therefore not recommended for women who are breastfeeding during therapy. Breastfeeding should also be avoided for at least 1 year after the last dose.

副作用

与任何其他药物一样，服用氟维司群可能会出现副作用。需要注意以下几点：

• 您可能不会出现以下列出的所有副作用。许多人可能几乎没有副作用。
• 副作用的严重程度可能因人而异，因此不要将您的副作用与其他人的经历进行比较。
• 停止治疗后，大多数副作用都会改善。
• 这些副作用大多数情况下都很容易控制，只需调整氟维司群的剂量或使用其他药物来缓解症状即可。请咨询您的医生或药剂师，了解可用的治疗方案。
• 不要隐瞒任何症状；当您感到任何不适时，请毫不犹豫地告诉您的医生或药剂师。

笔记：此列表并未涵盖所有副作用。如有任何疑问，请咨询医生。 

氟维司群的一些最常见的副作用是：

胃肠道 (GI) 影响

服用氟维司群时通常会出现腹痛、便秘、食欲下降、腹泻、恶心、口腔炎或呕吐。

注射部位疼痛

使用氟维司群后，注射部位很可能会感到疼痛。注射后数小时或数天内，注射部位可能会感到疼痛。此外，注射部位还可能出现轻微瘀伤、肿胀或发红。这些疼痛可以通过服用泰诺或美林等非处方止痛药来控制，但通常会在几天内自行缓解。开始任何新的治疗前，请咨询您的医生或药剂师。

过敏反应/超敏反应 

已有患者报告对氟维司群注射液或其任何成分出现过敏反应。过敏反应的症状可能包括皮疹；荨麻疹；瘙痒；皮肤肿胀、发红、起水疱或脱皮（伴或不伴发烧）；喘息；喉咙或胸部紧绷感；呼吸、吞咽或说话困难；声音异常嘶哑；或口腔、嘴唇、面部、舌头或喉咙肿胀。如果您出现任何这些症状，请立即就医。

激素副作用 

Since fulvestrant blocks and degrades the estrogen receptor, some people experience menopause-like symptoms. These may include hot flashes, increased sweating, and trouble sleeping. Fatigue can also occur; if you feel unusually tired or dizzy, use caution when driving or operating machinery.

其他常见的副作用可能包括：

• 咳嗽
• 咽喉刺激
• 流感样症状
• 感染
• 尿路感染（UTI）
• 腿部无力
• 瘀伤或出血
• 沮丧
• 胸痛
• 手臂或腿肿胀

防范措施

除非得到医生的批准，否则通常不建议在以下情况下使用氟维司群： 

• 对氟维司群、苯甲醇或注射剂中的任何其他成分过敏的患者。 这些反应可能导致全身皮疹、呼吸急促、喘息、头晕、口周或眼周肿胀、心率加快和出汗。如果您出现任何这些症状，请停止使用氟维司群，并立即就医。
• 有肝病史或长期饮酒史的患者。 肝功能不全的患者可能需要较低剂量。对于有长期饮酒史的患者，建议完全避免使用氟维司群，因为它含有约96%的乙醇。Fulvestrant还会升高肝酶，包括 AST 和 ALT 水平。
• Patients with bleeding or blood-clotting problems. Bleeding or clotting problems may worsen with the use of fulvestrant. These problems may exhibit symptoms like bruising; black, tarry, or bloody stools; bleeding gums; blood in the urine; coughing up blood; cuts that take a long time to stop bleeding; nosebleeds; throwing up blood or vomit that looks like coffee grounds.

常见问题解答

氟维司群是化疗药物吗？

Fulvestrant is not considered traditional cytotoxic chemotherapy. It is an endocrine (hormonal) therapy — specifically a selective estrogen receptor degrader (SERD)—used to treat estrogen receptor–positive breast cancer by blocking and degrading the estrogen receptor.

应如何服用氟维司群？

氟维司群预充式注射器仅供臀部肌肉注射使用。应使用两支预充式注射器（每支5毫升，每支250毫克），每侧臀部各一支，每次缓慢注射，每次注射时间1至2分钟。每月总剂量应为500毫克。每侧臀部注射量不得超过5毫升（一支注射器）。

你能接触氟维司群吗？

Fulvestrant is considered a hazardous medication. Therefore, it is highly recommended to wear gloves when administering the drug. Store securely in its original container until time of use.