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letrozole (let-roe-zole)



Therapeutic: antineoplastics

Pharmacologic: aromatase inhibitors


First-line treatment of postmenopausal women with hormone receptor–positive or hormone receptor unknown metastatic or advanced breast cancer. Advanced breast cancer in postmenopausal patients with disease progression despite antiestrogen therapy. Extended adjuvant treatment of postmenopausal early breast cancer already treated with 5 yr of tamoxifen.


Inhibits the enzyme aromatase, which is partially responsible for conversion of precursors to estrogen. Therapeutic Effects: Lowers levels of circulating estrogen, which may halt progression of estrogensensitive breast cancer. Decreased risk of recurrence/metastatic disease.

Adverse Reactions/Side Effects

CNS: anxiety, depression, dizziness, drowsiness, fatigue, headache, vertigo, weakness. Resp: coughing, dyspnea, pleural effusion. CV: chest pain, edema, hypertension, cerebrovascular events, thromboembolic events. GI: nausea, abdominal pain, anorexia, constipation, diarrhea, dyspepsia, vomiting. Derm: alopecia, hot flashes, increased sweating, pruritus, rash. F and E: hypercalcemia. Metab: hypercholesterolemia, weight gain. MS: musculoskeletal pain, arthralgia, fractures.


Examination and Evaluation

  • Monitor signs of stroke (sudden severe headache, confusion, nausea, vomiting, paralysis, numbness, speech problems, visual disturbances) or pulmonary embolism (sudden shortness of breath, chest pain, cough, bloody sputum). Notify physician of these signs immediately.

  • Monitor signs of pleural effusion, including cough, shortness of breath, chest pain, or labored breathing. Report these signs to the physician immediately.

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

  • Assess blood pressure periodically and compare to normal values (See Appendix F). Report a sustained increase in blood pressure (hypertension) to the physician.

  • 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 signs of high calcium levels (hypercalcemia), including muscle pain, weakness, joint pain, confusion, and lethargy. Notify physician because severe cases can lead to life-threatening arrhythmias and paralysis.

  • Monitor personality changes, including anxiety and depression. Notify physician if these changes become problematic.

  • Assess dizziness, weakness, or vertigo that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

  • Periodically assess body weight and other anthropometric measures (body mass index, body composition). Report a rapid or unexplained weight gain. Blood tests may also be necessary to monitor high cholesterol levels.


  • 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.

  • Because of potential cardiopulmonary problems, use caution ...

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