Letrozole Viatris

Letrozole, the active ingredient in Letrozole Viatris, is an aromatase inhibitor presented as oral tablets for oral use. It is employed to treat hormone receptor‑positive breast cancer in postmenopausal women by lowering estrogen levels.

GNH USA supplies Letrozole Viatris as a licensed, GDP‑compliant international pharmaceutical supplier serving oncology centres worldwide.

Letrozole is an aromatase inhibitor used in the management of estrogen‑dependent breast cancer. It works by reducing estrogen production, thereby limiting tumor growth.

- Hormone receptor‑positive breast cancer (postmenopausal): reduces tumor proliferation by lowering circulating estrogen. - Adjuvant therapy for early‑stage hormone receptor‑positive breast cancer: helps prevent disease recurrence after surgery. - Metastatic hormone receptor‑positive breast cancer (postmenopausal): slows disease progression and extends survival.

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

Common Side Effects: - Hot flashes: sudden feeling of warmth and sweating. - Fatigue: persistent tiredness not relieved by rest. - Nausea: upset stomach with urge to vomit. - Arthralgia: joint pain or stiffness. - Headache: mild to moderate head pain. - Increased sweating: excessive perspiration.

Serious or Rare Side Effects: - Severe liver injury: jaundice, elevated liver enzymes. - Thromboembolic events: deep vein thrombosis or pulmonary embolism. - Bone fractures: increased risk of osteoporosis‑related breaks. - QT interval prolongation: potential cardiac arrhythmia. - Interstitial lung disease: breathing difficulties and cough. - Anaphylaxis: severe allergic reaction with rash, swelling, and airway compromise.

Before initiating letrozole therapy, several safety considerations should be addressed.

- Bone health assessment: evaluate risk of osteoporosis and consider calcium/vitamin D supplementation. - Liver function monitoring: perform baseline and periodic liver enzyme tests. - Lipid profile check: monitor cholesterol levels during treatment. - Pregnancy avoidance: letrozole is contraindicated in pregnancy (Category X). - Cardiovascular caution: assess history of thromboembolic disease before use. - Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

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

Major Interactions (Avoid): - Strong CYP3A4 inhibitors (e.g., ketoconazole): may increase letrozole exposure and toxicity. - Estrogen‑containing therapy (e.g., hormone replacement): reduces letrozole effectiveness. - Warfarin: may potentiate anticoagulant effect and raise INR.

Moderate Interactions (Monitor Closely): - Moderate CYP3A4 inhibitors (e.g., erythromycin): may modestly raise plasma levels. - CYP2C19 inhibitors (e.g., fluoxetine): could alter metabolism. - Statins and glucocorticoids: monitor for additive hepatic effects.