Letrozol Stada (Letrozole)

• Letrozole is an aromatase inhibitor used in hormone‑dependent breast cancer therapy.
• Hormone receptor‑positive breast cancer (early stage): Reduces estrogen levels to inhibit tumor growth.
• Metastatic breast cancer (postmenopausal): Helps control disease progression.
• Adjuvant therapy for breast cancer (postmenopausal): Decreases risk of recurrence.

• Letrozole selectively and competitively inhibits the aromatase enzyme (CYP19A1) in peripheral tissues, blocking the conversion of androstenedione and testosterone to estrone and estradiol. By suppressing estrogen synthesis, circulating estrogen concentrations fall markedly, depriving estrogen‑dependent tumor cells of a growth stimulus and thereby slowing or halting cancer progression. The inhibition is reversible and dose‑dependent, leading to sustained low estrogen levels throughout treatment.

Common Side Effects

• Hot flashes: Sudden feeling of warmth and sweating.
• Joint and muscle pain: Discomfort in joints or muscles.
• Fatigue: Persistent tiredness not relieved by rest.
• Nausea: Mild to moderate upset stomach.

Serious or Rare Side Effects

• Severe liver injury: Jaundice, dark urine, abdominal pain.
• Bone fractures: Increased risk due to reduced bone density.
• Deep vein thrombosis or pulmonary embolism: Swelling, pain, shortness of breath.
• Severe allergic reactions: Rash, itching, swelling, difficulty breathing.

Before initiating therapy, consider the following precautions:

• Monitor bone health: Assess bone mineral density regularly.
• Evaluate liver function: Perform baseline and periodic liver enzyme tests.
• Assess cardiovascular risk: Review history of clotting disorders.
• Use caution in severe osteoporosis: May exacerbate bone loss.
• Contraindicated in pregnancy: Avoid use in pregnant or nursing women.
• Store at room temperature: Keep in the original container, protect from moisture and light.

Letrozole may interact with several medicines; review patient medication lists carefully.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): May reduce letrozole efficacy.
• Estrogen‑containing hormonal contraceptives: May counteract aromatase inhibition.
• Warfarin: Potentially increased INR and bleeding risk.

Moderate Interactions (Monitor Closely)

• CYP2C19 inhibitors (e.g., fluconazole): May raise letrozole plasma levels.
• Selective serotonin reuptake inhibitors (SSRIs): May modestly affect metabolism.
• Diuretics: May alter electrolyte balance, requiring monitoring.