Letrozol Orifarm (Letrozole)

Letrozole acts on the estrogen‑dependent pathway of breast cancer, providing endocrine therapy for hormone‑responsive disease.

• Postmenopausal estrogen receptor‑positive breast cancer: lowers recurrence risk and slows disease progression.
• Adjuvant treatment of hormone‑responsive breast cancer: improves disease‑free survival after surgery.
• Metastatic breast cancer in postmenopausal women: delays tumor growth and extends survival.

• Letrozole is a reversible, non‑steroidal inhibitor of the aromatase enzyme. By binding to the enzyme's active site, it blocks the conversion of androgens to estrogens in peripheral tissues, leading to markedly reduced circulating estrogen levels. The resulting hypo‑estrogenic state deprives estrogen‑dependent tumor cells of growth stimulation, thereby inhibiting tumor proliferation.

Letrozole may cause a range of adverse reactions, from mild to severe. Patients should be monitored for both common and serious events.

Common Side Effects

• Hot flashes: transient episodes of intense warmth.
• Joint and muscle pain: arthralgia and myalgia.
• Fatigue: persistent tiredness.
• Nausea: mild to moderate upset stomach.
• Headache: occasional throbbing pain.
• Dizziness: light‑headed sensation.

Serious or Rare Side Effects

• Severe liver injury: jaundice, elevated enzymes.
• Pulmonary embolism: sudden shortness of breath.
• Bone fracture: increased risk due to reduced bone density.
• Allergic reaction: rash, swelling, or anaphylaxis.
• Elevated cholesterol: hyperlipidaemia.
• Cardiac arrhythmia: QT prolongation.

Before initiating Letrozol Orifarm, clinicians should assess patient-specific risk factors and monitor therapy closely.

• Bone health monitoring: perform baseline and periodic DEXA scans.
• Liver function assessment: check transaminases prior to and during treatment.
• Cardiovascular risk evaluation: monitor blood pressure and lipid profile.
• Pregnancy avoidance: contraindicated in pregnancy (Category X).
• Elderly caution: start at lowest effective dose and monitor for toxicity.
• Store below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Letrozole can interact with several medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce letrozole plasma levels.
• Estrogen‑containing hormonal therapy: antagonizes letrozole's anti‑estrogen effect.
• Live hormonal vaccines: potential reduced vaccine efficacy.

Moderate Interactions (Monitor Closely)

• Warfarin: may increase INR, requiring closer coagulation monitoring.
• Cholesterol‑lowering agents (statins): possible additive effect on liver enzymes.
• Antidepressants (SSRIs): may influence hormone metabolism.
• Antifungal azoles (ketoconazole): can increase letrozole exposure.
• Herbal supplements (St. John’s wort): may induce metabolism and lower efficacy.