TORE-em-i-feen

Therapeutic Classification: antineoplastics

Pharmacologic Classification: antiestrogens

• Metastatic breast cancer in postmenopausal women with estrogen receptor–positive or unknown tumors.

• Exerts antiestrogenic effects by competing for estrogen-binding sites found in breast cancers.

• Regression of breast cancer.

Absorption: Well absorbed following oral administration.

Distribution: Widely distributed to tissues.

Protein Binding: 99.5%.

Metabolism/Excretion: Extensively metabolized; undergoes enterohepatic circulation.

Half-life: 5 days.

(plasma concentrations)

†Steady-state plasma concentrations occur after 4–6 wk.

Contraindicated in:

• Hypersensitivity
• History of thromboembolic disease
• Congenital or acquired QT prolongation, hypokalemia, or hypomagnesemia
• OB: Pregnancy
• Lactation: Lactation.

Use Cautiously in:

• Bone metastases (↑ risk of hypercalcemia)
• HF
• Hepatic impairment
• Pre-existing endometrial hyperplasia (avoid long-term treatment).

CV: angina, arrhythmias, edema, HF, MI, QT interval prolongation, thrombophlebitis, TORSADES DE POINTES.

Derm: sweating.

EENT: blurred vision, cataracts, corneal keratopathy, dry eyes, glaucoma.

Endo: hot flashes.

F and E: hypercalcemia.

GI: nausea, HEPATOTOXICITY, vomiting.

GU: vaginal discharge, ENDOMETRIAL CANCER, endometrial hyperplasia/hypertrophy, uterine polyps, vaginal bleeding.

Hemat: anemia.

Neuro: depression, dizziness, headache, lethargy.

Resp: PULMONARY EMBOLISM.
Misc: tumor flare.

Drug-Drug:

• QT interval prolonging drugs may ↑ the risk of torsades de pointes; avoid concurrent use.
• Strong CYP3A4 inhibitors, including ketoconazole, itraconazole, clarithromycin, atazanavir, nefazodone, nelfinavir, ritonavir, and voriconazole, may ↑ levels; avoid concurrent use.
• Strong CYP3A4 inducers, including dexamethasone, phenytoin, carbamazepine, rifampin, rifabutin, and phenobarbital, may ↓ levels and effectiveness.
• Concurrent use of agents that ↓ urinary excretion of calcium (thiazide, diuretics) may ↑ the risk of hypercalcemia.
• May ↑ the effects of warfarin and phenytoin.

Drug-Natural Products:

• St. John's wort may ↓ levels and effectiveness.

• PO (Adults): 60 mg once daily.

(Generic available)

• Tablets: 60 mg;

• Assess for an increase in bone or tumor pain. May be indicative of tumor flare and hypercalcemia if during early therapy. Confer with health care professional regarding analgesics. This transient pain usually resolves despite continued therapy.
• Gynecologic examinations should be done regularly; may cause variations in Papanicolaou and vaginal smears.

• Monitor CBC, platelets, and calcium levels prior to and periodically throughout therapy. May cause transient hypercalcemia in patients with metastases to bone. An estrogen receptor assay should be assessed prior to initiation of therapy.
  • Monitor hepatic function tests periodically during therapy. May cause ↑AST, alkaline phosphatase, and bilirubin concentrations.

• Hypokalemia and hypomagnesemia should be corrected prior to starting therapy.
• PO: Administer once daily.

• Instruct patient to take medication exactly as directed. If a dose is missed, it should be omitted.
• Advise patient to report bone pain to health care professional promptly. Pain may be severe. Inform patient that this may be an indication of the drug’s effectiveness and will resolve over time. Analgesics should be ordered to control pain.
• Advise patient that medication may cause hot flashes. Notify health care professional if these become bothersome.
• Instruct patient to notify health care professional promptly if pain or swelling of legs, shortness of breath, weakness, sleepiness, confusion, nausea, vomiting, dizziness, headache, loss of appetite, or blurred vision occurs. Patient should also report menstrual irregularities, vaginal bleeding, or pelvic pain or pressure.
• May cause vaginal bleeding. Advise patient of importance of baseline and annual gynecological exams during therapy and to notify health care professional if vaginal bleeding, changes in vaginal discharge, or pelvic pain or pressure occur.
• May cause fetal harm. May also induce ovulation. Advise patient to use a nonhormonal method of contraception during and for 1 mo after the course of therapy and to avoid breastfeeding during therapy.

• Decrease in the spread of breast cancer.

Fareston