Lerana (Letrozole)

Letrozole acts on estrogen‑dependent breast cancer pathways and is indicated for the following conditions:

• Adjuvant treatment of hormone‑receptor positive breast cancer in postmenopausal women: reduces risk of disease recurrence after surgery.
• Metastatic breast cancer in postmenopausal women: helps control tumor progression and prolongs survival.
• Hormone‑sensitive breast cancer in postmenopausal patients: lowers circulating estrogen levels to inhibit tumor growth.

• Letrozole selectively inhibits the aromatase enzyme, which converts adrenal and peripheral androgens into estrogens. By blocking this conversion, systemic estrogen concentrations decline, depriving estrogen‑dependent tumor cells of a growth stimulus and thereby slowing or halting cancer progression.

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

Common Side Effects

• Hot flashes: transient episodes of intense warmth.
• Joint and muscle pain: aching or stiffness in limbs.
• Fatigue: persistent tiredness not relieved by rest.
• Nausea: mild to moderate upset stomach.
• Headache: pressure or throbbing pain.
• Dizziness: sensation of light‑headedness.

Serious or Rare Side Effects

• Osteoporotic fractures: increased risk due to bone density loss.
• Deep vein thrombosis: formation of blood clots in deep veins.
• Elevated liver enzymes: signs of hepatic stress.
• Severe allergic reaction: rash, swelling, or difficulty breathing.
• Pulmonary embolism: blockage of lung arteries.
• Cardiovascular events: rare heart‑related complications.

Before initiating Letrozole therapy, several safety considerations should be observed.

• Monitor bone health: assess bone mineral density periodically due to estrogen depletion.
• Evaluate liver function: check hepatic enzymes before and during treatment.
• Assess cardiovascular risk: consider history of thromboembolic disease.
• Review concomitant medications: avoid drugs that may interfere with aromatase inhibition.
• Store at ambient temperature below 25°C: keep in the original container, protect from moisture.

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

Major Interactions (Avoid)

• Estrogen replacement therapy: antagonizes Letrozole’s intended effect.
• Strong CYP2C19 inhibitors (e.g., fluconazole): may raise Letrozole plasma levels.
• Tamoxifen: concurrent use reduces therapeutic benefit of both agents.

Moderate Interactions (Monitor Closely)

• Warfarin: Letrozole may potentiate anticoagulant effect, increasing INR.
• CYP3A4 inducers (e.g., rifampin): may lower Letrozole concentrations.
• SSRIs (e.g., fluoxetine): may increase incidence of hot flashes.
• Antihypertensives: monitor blood pressure as Letrozole can affect vascular tone.