Nurses Compass
Drug Guide
Anastrozole
Classification
Therapeutic: Hormone therapy / Antineoplastic agent
Pharmacological: Non-steroidal Aromatase Inhibitor
FDA Approved Indications
- Postmenopausal women with hormone receptor-positive breast cancer as adjuvant therapy.
- Treatment of advanced or metastatic hormone receptor-positive breast cancer in postmenopausal women.
Mechanism of Action
Anastrozole inhibits aromatase, an enzyme responsible for converting androgens to estrogens, thereby reducing estrogen levels and limiting the growth of estrogen receptor-positive breast cancer cells.
Dosage and Administration
Adult: Typically 1 mg orally once daily. Exact dosing should be tailored based on patient response and tolerance.
Pediatric: Not approved for pediatric use.
Geriatric: No specific dosage adjustment required, but monitor for adverse effects as in adults.
Renal Impairment: No specific adjustment needed; use caution.
Hepatic Impairment: Use with caution; no specific dosage adjustment established.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Widely distributed in body tissues.
Metabolism: Primarily hepatic via hydroxylation and conjugation.
Excretion: Renal and fecal routes.
Half Life: Approximately 40-50 hours.
Contraindications
- Known hypersensitivity to anastrozole or any component of the formulation.
Precautions
- Use with caution in severe liver impairment, osteoporosis risk, and cardiovascular disease. Monitor bone mineral density regularly.
Adverse Reactions - Common
- Hot flashes (Common)
- Arthralgia (Common)
- Weakness (Common)
- Nausea (Common)
Adverse Reactions - Serious
- Osteoporosis and fractures (Serious)
- Cardiovascular events (Serious)
- Thromboembolism (Serious)
- Severe allergic reactions (Serious)
Drug-Drug Interactions
- Tamoxifen (potentially antagonistic effect on anastrozole)
- Estrogen-containing medications
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor bone density, lipid profile, and cardiovascular status regularly. Assess for symptoms of osteoporosis or fractures.
Diagnoses:
- Risk for osteoporosis
- Risk for cardiovascular disease
Implementation: Administer once daily; recommend calcium and vitamin D supplementation; encourage weight-bearing exercises.
Evaluation: Evaluate bone density periodically; monitor for signs of cardiovascular issues.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report any joint pain, bone pain, or signs of osteoporosis.
- Use calcium and vitamin D as recommended.
- Avoid estrogen-containing products.
Special Considerations
Black Box Warnings:
- Increased risk of osteoporosis and fractures during therapy.
Genetic Factors: No current specific genetic considerations.
Lab Test Interference: May decrease bone density markers; monitor serum lipid profiles and bone mineral density.
Overdose Management
Signs/Symptoms: No specific overdose symptoms identified, but possible excess hormonal suppression.
Treatment: Supportive care; no specific antidote. Consultation with poison control is recommended.
Storage and Handling
Storage: Store at room temperature between 20°C and 25°C (68°F to 77°F).
Stability: Stable for at least 2 years when stored properly.