Home Drug Guide Letrozole

Drug Guide

Generic Name

Letrozole

Brand Names Femara

Classification

Therapeutic: Antineoplastic agent (hormone therapy)

Pharmacological: Aromatase inhibitor

FDA Approved Indications

  • Adjuvant treatment of hormone receptor-positive early breast cancer in postmenopausal women
  • Treatment of hormone receptor-positive metastatic breast cancer in postmenopausal women

Mechanism of Action

Letrozole inhibits the enzyme aromatase, which is responsible for converting androgens into estrogens. By reducing estrogen levels, it decreases the growth of estrogen-dependent breast cancer cells.

Dosage and Administration

Adult: Initially, 2.5 mg once daily. May be taken with or without food.

Pediatric: Not recommended for pediatric patients.

Geriatric: No specific dosage adjustment necessary, but elderly patients should be monitored closely.

Renal Impairment: No specific dosage adjustment recommended.

Hepatic Impairment: Use with caution; no specific dosage adjustment.

Pharmacokinetics

Absorption: Well absorbed with peak plasma concentrations within 2 hours.

Distribution: Extensively distributed; approximately 60% bound to plasma proteins.

Metabolism: Primarily metabolized in the liver via hydroxylation and glucuronidation.

Excretion: Excreted mainly in urine; small amount in feces.

Half Life: Approximately 2 days (40-50 hours).

Contraindications

  • Hypersensitivity to letrozole or any component of the formulation.

Precautions

  • History of osteoporosis or risk factors for osteoporosis; may increase fracture risk.
  • Monitor bone mineral density periodically.
  • Use during pregnancy is contraindicated; it can cause fetal harm.
  • Lactation: Not recommended during breastfeeding.

Adverse Reactions - Common

  • Hot flashes (Common)
  • Arthralgia (Common)
  • Fatigue (Common)
  • Nausea (Common)

Adverse Reactions - Serious

  • Osteoporosis and fractures (Less common)
  • Cardiovascular events (e.g., chest pain, arrhythmias) (Rare)
  • Elevated liver enzymes (Rare)

Drug-Drug Interactions

  • Tamoxifen (antagonizes letrozole activity)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Assess breast cancer status, menopausal status, bone mineral density, cardiovascular status.

Diagnoses:

  • Risk for osteoporosis related to decreased estrogen levels.
  • Risk for injury due to fractures.

Implementation: Administer as prescribed, monitor for adverse effects, encourage bone health measures.

Evaluation: Monitor tumor response, bone density, and adverse reactions.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report any signs of osteoporosis (e.g., fractures), cardiovascular symptoms, or severe side effects.
  • Maintain calcium and vitamin D intake, engage in weight-bearing exercises.
  • Avoid pregnancy; use effective contraception.

Special Considerations

Black Box Warnings:

  • Fetal harm; contraindicated in pregnancy.

Genetic Factors: No specific genetic markers required for use.

Lab Test Interference: May affect serum cholesterol levels.

Overdose Management

Signs/Symptoms: Unknown, but may include hormonal effects or nausea.

Treatment: Supportive care; no specific antidote. Consult poison control.

Storage and Handling

Storage: Store at room temperature, 20°C to 25°C (68°F to 77°F).

Stability: Stable when stored properly until the expiration date.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.