Fulvestrant

INTRODUCTION

Indications

Treatment of hormone receptor–positive metastatic breast cancer in postmenopausal women with progressive disease that has not responded to antiestrogen therapy.

Action

Competitively binds to estrogen receptors. Binding results in down-regulation of estrogen receptor protein in cancerous breast tissue. Therapeutic Effects: Decreased progression of hormone receptor-positive breast cancer.

Adverse Reactions/Side Effects

CNS: headache, weakness, anxiety, depression, dizziness, insomnia. EENT: pharyngitis. Resp: dyspnea, increased cough. CV: vasodilation (hot flushes), chest pain, edema. GI: abdominal pain, constipation, diarrhea, nausea, vomiting, anorexia. GU: pelvic pain, urinary tract infection. Derm: rash, sweating. Local: pain/inflammation at injection site. Hemat: anemia. MS: back pain, bone pain, arthritis. Neuro: paresthesia. Misc: fever, flu syndrome.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor signs of anemia, including unusual weakness, fatigue, shortness of breath with exertion, and bruising. Notify physician if these signs occur.

• Assess peripheral edema using girth measurements, volume displacement, and measurement of pitting edema (See Appendix N). Report increased swelling in feet and ankles or a sudden increase in body weight due to fluid retention.

• Monitor any chest pain or difficult, labored breathing. Attempt to differentiate whether symptoms are drug induced or caused by cardiovascular dysfunction (e.g., angina that occurs during exercise).

• Assess any back pain, bone pain, pelvic pain, or other musculoskeletal pain. Suggest additional tests (radiography, MRI) as needed to rule out fracture.

• Monitor and report depression, anxiety, or other changes in mood and behavior.

• Assess signs of paresthesia (numbness, tingling) or muscle twitching. Perform objective tests, including electroneuromyography and sensory testing to document any drug-related neuropathic changes.

• Monitor IM injection site for pain, swelling, and irritation. Report prolonged or excessive injection-site reactions to the physician.

Interventions

• For patients who are medically able to begin exercise, implement appropriate resistive exercises and aerobic training to maintain muscle strength and aerobic capacity during cancer chemotherapy or to help restore function after chemotherapy.

Patient/Client-Related Instruction

• Instruct patient to report other troublesome side effects such as severe or prolonged headache, sleep loss, cough, throat irritation, hot flashes, flu-like symptoms, urinary tract infection, skin reactions (rash, sweating), or GI problems (nausea, diarrhea, vomiting, constipation, abdominal pain, loss of appetite).

Pharmacokinetics

Absorption: Well absorbed following IM administration.

Distribution: Rapidly and extensively distributed.

Protein Binding: 99%.

Metabolism and Excretion: Mostly metabolized by the liver; negligible renal elimination.

Half-life: 40 days.