Letrozol Denk (Letrozole)

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

• Hormone receptor‑positive breast cancer in postmenopausal women: reduces estrogen levels to inhibit tumor progression.
• Metastatic breast cancer in postmenopausal women: helps control disease spread.
• Adjuvant therapy for early‑stage disease: improves disease‑free survival.

• Letrozole selectively and non‑steroidally inhibits the aromatase enzyme, which converts androgens to estrogens in peripheral tissues. By blocking this conversion, systemic estrogen concentrations decline, depriving estrogen‑dependent tumor cells of a growth stimulus and thereby limiting proliferation of hormone‑sensitive breast cancer cells.

Letrozole may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Hot flashes: transient feeling of warmth and sweating.
• Joint pain: aching or stiffness in joints.
• Fatigue: persistent tiredness.
• Nausea: upset stomach and urge to vomit.
• Headache: mild to moderate head discomfort.
• Increased cholesterol: elevation of serum lipid levels.

Serious or Rare Side Effects

• Severe liver injury: hepatitis or hepatic failure.
• Bone fracture: increased risk due to bone density loss.
• Deep vein thrombosis: clot formation in deep veins.
• Pulmonary embolism: blockage of pulmonary arteries.
• Allergic reactions: rash, swelling, or anaphylaxis.
• Myocardial infarction: heart attack.

Before initiating therapy, clinicians should evaluate patient‑specific risk factors and monitor for adverse events.

• Monitor bone health: assess risk of osteoporosis and consider calcium/vitamin D supplementation.
• Check liver function: perform baseline and periodic liver enzyme tests.
• Assess cardiovascular risk: monitor lipid profile and blood pressure.
• Avoid use in pregnancy: teratogenic, contraindicated.
• Discontinue if severe adverse reactions occur.
• Store at ambient temperature: keep in original container, protect from moisture and light.

Letrozole can interact with other medicines that affect its metabolism or hormonal pathways.

Major Interactions (Avoid)

• Concurrent estrogen replacement therapy: may reduce efficacy of letrozole.
• Strong CYP2C19 inhibitors (e.g., fluconazole): increase plasma levels of letrozole.
• Strong CYP2C19 inducers (e.g., rifampicin): decrease plasma levels of letrozole.

Moderate Interactions (Monitor Closely)

• Warfarin: may alter anticoagulant effect, monitor INR.
• Tamoxifen: potential antagonistic effect on estrogen pathways.
• Antidepressants (SSRIs): may affect metabolism, observe for side effects.