Letrozolo Aurobindo Italia (Letrozole)

Letrozole is used in the management of hormone‑dependent breast cancer, targeting estrogen‑driven disease pathways.

• Adjuvant therapy for ER‑positive early‑stage breast cancer: reduces risk of recurrence after surgery.
• Metastatic ER‑positive breast cancer in postmenopausal women: slows disease progression and extends survival.
• Neoadjuvant treatment before surgery for ER‑positive tumors: may shrink tumor size to facilitate breast‑conserving surgery.

• Letrozole reversibly binds to the aromatase enzyme (CYP19A1) in peripheral tissues, inhibiting the conversion of androstenedione and testosterone to estrone and estradiol. By blocking this final step of estrogen biosynthesis, systemic estrogen concentrations decline, depriving estrogen‑dependent tumor cells of growth stimulation. The inhibition is dose‑dependent and persists for several days after dosing, providing sustained estrogen suppression.

Letrozole may cause a range of adverse reactions, which are generally classified by frequency and severity.

Common Side Effects

• Hot flashes: sudden feeling of warmth and sweating.
• Joint and muscle pain: arthralgia and myalgia.
• Fatigue: persistent tiredness.
• Nausea: mild gastrointestinal upset.
• Headache: occasional throbbing pain.

Serious or Rare Side Effects

• Severe liver injury: elevated transaminases or hepatitis.
• Bone fracture: increased risk of osteoporosis‑related fractures.
• Pulmonary embolism: sudden shortness of breath and chest pain.
• Allergic reaction: rash, swelling, or anaphylaxis.

When prescribing Letrozole, clinicians should consider several safety measures to minimize risks.

• Monitor bone health: assess baseline bone mineral density and consider calcium/vitamin D supplementation.
• Check liver function: perform baseline and periodic liver enzyme tests.
• Evaluate cardiovascular risk: monitor lipid profile and blood pressure.
• Avoid use in premenopausal women: drug is not indicated for this population.
• Store at ambient temperature: keep in original container, protect from moisture and light.

Letrozole can interact with other medicines, affecting its efficacy or safety.

Major Interactions (Avoid)

• Concomitant estrogen‑containing hormone therapy: antagonizes letrozole’s estrogen‑lowering effect.
• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): markedly reduce plasma concentrations.
• Tamoxifen: opposing mechanisms may diminish therapeutic benefit.

Moderate Interactions (Monitor Closely)

• Warfarin: letrozole may increase INR, requiring closer monitoring.
• CYP2C19 inhibitors (e.g., fluconazole, omeprazole): may raise letrozole levels.
• Statins metabolized by CYP3A4 (e.g., simvastatin): monitor for myopathy.
• Antidepressants affecting CYP2D6 (e.g., fluoxetine): observe for altered metabolism.