ANASTROZOLE

(a-nas'tro-zole)

Arimidex
Classifications: antineoplastic; nonsteroidal aromatase inhibitor;
Therapeutic: antineoplastic
Pregnancy Category: D

Availability

1 mg tablets

Action

Anastrozole is a potent and selective nonsteroidal aromatase inhibitor that converts estrone to estradiol. It lowers serum estrogen levels in postmenopausal women without interfering with adrenal steroid synthesis.

Therapeutic Effect

Inhibiting the biosynthesis of estrogens is one way to deprive tumors of estrogens, and thus restrict tumor growth.

Uses

Early and advanced breast cancer in postmenopausal women.

Contraindications

Pregnancy (category D), lactation, premenopausal women, postmenopausal hormone replacement therapy; severe hepatic disease, children.

Cautious Use

Mild to moderate hepatic disease.

Route & Dosage

Breast Cancer
Adult: PO 1 mg once daily

Administration

Oral

Give on an empty stomach, 1 h before or 2 h after meals, because food affects extent of absorption.
Store at 20°–25° C (68°–77° F).

Adverse Effects (≥1%)

CNS: Asthenia, headache, hot flushes, pain, dizziness, depression, paresthesia, malaise, insomnia, confusion, anxiety, nervousness. CV: Chest pain, hypertension, thrombophlebitis, edema. GI: Diarrhea, nausea, vomiting, constipation, abdominal pain, anorexia, dry mouth, increased liver function tests (ALT, AST, GGT). Respiratory: Dyspnea, cough, pharyngitis, bronchitis, rhinitis, sinusitis. Other: Rash, peripheral edema, pelvic pain, flu-like syndrome.

Pharmacokinetics

Absorption: Rapidly absorbed from GI tract. Distribution: 40% protein bound. Metabolism: 85% metabolized in liver to inactive metabolites. Elimination: 10% excreted unchanged; 60% as metabolites in urine. Half-Life: 50 h.

Nursing Implications

Assessment & Drug Effects

Lab Tests: Monitor periodically liver enzymes, CBC with differential, alkaline phosphatases, total cholesterol, and lipid profile.
Assess for hypertension, complications of edema, thrombotic events, and signs of liver toxicity.

Patient & Family Education

Recognize common adverse effects and seek information on measures to control discomfort.
Seek medical attention if you experience chest pain, calf pain, or shortness of breath; unexplained loss of appetite or nausea; jaundice.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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