Letrozol Actavis (Letrozole)

Letrozol Actavis is an aromatase inhibitor used in the management of hormone‑dependent breast cancer. It acts on estrogen‑driven disease pathways.

• Adjuvant therapy: reduces the risk of disease recurrence after surgery in postmenopausal women.
• Metastatic disease: slows tumor progression and extends survival in advanced hormone‑receptor‑positive breast cancer.
• Neoadjuvant setting: may shrink tumors before definitive surgery, facilitating breast‑conserving procedures.

• Letrozole reversibly binds to the aromatase enzyme, blocking the conversion of androstenedione and testosterone into estrone and estradiol. By inhibiting peripheral estrogen synthesis, it markedly reduces circulating estrogen levels, depriving estrogen‑dependent breast cancer cells of a key growth stimulus.

Letrozol Actavis may cause a range of adverse reactions. Patients should be monitored for both frequent and uncommon events.

Common Side Effects

• Hot flashes: sudden feeling of warmth, often with sweating.
• Joint and muscle pain: aching in knees, hips, or back.
• Fatigue: persistent tiredness not relieved by rest.
• Nausea: mild to moderate upset stomach.
• Headache: pressure or throbbing pain.
• Increased sweating: excessive perspiration.

Serious or Rare Side Effects

• Severe liver injury: jaundice, dark urine, elevated liver enzymes.
• Bone fractures: increased risk of osteoporosis‑related breaks.
• Pulmonary embolism: sudden shortness of breath, chest pain.
• Anaphylaxis: severe allergic reaction with swelling, rash, or difficulty breathing.
• QT interval prolongation: heart rhythm disturbances that may cause fainting.

Before initiating Letrozol Actavis, clinicians should consider several safety measures.

• Pregnancy contraindication: avoid use in pregnancy; teratogenic risk is high.
• Menopause verification: confirm postmenopausal status to ensure therapeutic relevance.
• Bone health monitoring: assess bone mineral density periodically.
• Liver function monitoring: check hepatic enzymes before and during therapy.
• CYP2A6 interaction awareness: avoid strong inhibitors that may raise drug levels.
• Hypersensitivity avoidance: discontinue if signs of allergic reaction appear.
• Store at ambient temperature: keep below 25 °C in the original container, protect from moisture and light.

Letrozol Actavis can interact with other medicines, altering its efficacy or safety.

Major Interactions (Avoid)

• Estrogen replacement therapy: may counteract aromatase inhibition and reduce therapeutic effect.
• Strong CYP2A6 inhibitors (e.g., fluvoxamine): can increase letrozole plasma concentrations, raising toxicity risk.

Moderate Interactions (Monitor Closely)

• Tamoxifen: antagonistic actions may diminish overall anti‑cancer benefit.
• Warfarin: letrozole may enhance anticoagulant effect, requiring INR monitoring.
• Cholestyramine or other bile‑acid sequestrants: can lower letrozole absorption, potentially reducing efficacy.