Letrozol Sandoz (Letrozole)

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

• Early‑stage hormone receptor‑positive breast cancer: reduces recurrence risk after surgery in postmenopausal women.
• Metastatic hormone receptor‑positive breast cancer: slows disease progression in postmenopausal women.
• Extended adjuvant therapy after initial treatment: further decreases the chance of cancer returning.

• Letrozole binds reversibly to the aromatase enzyme, a non‑steroidal inhibitor that blocks the conversion of androgens to estrogens. By reducing systemic estrogen levels, it deprives estrogen‑dependent tumor cells of a growth stimulus, thereby inhibiting proliferation of hormone‑sensitive breast cancer cells.

Letrozole may cause a range of adverse reactions, which are generally categorized by frequency and severity.

Common Side Effects

• Hot flashes: sudden feeling of warmth and sweating.
• Joint and muscle pain: aching in limbs and back.
• Fatigue: persistent tiredness not relieved by rest.
• Nausea: mild to moderate upset stomach.
• Headache: intermittent pressure or throbbing pain.
• Elevated cholesterol: increase in blood lipid levels.

Serious or Rare Side Effects

• Osteoporosis or severe bone loss: increased fracture risk.
• Liver function abnormalities: elevated transaminases.
• Cardiovascular events: hypertension or thromboembolic episodes.
• Severe allergic reactions: rash, swelling, or anaphylaxis.
• Interstitial lung disease: breathing difficulties and cough.

When prescribing Letrozole, clinicians should consider several precautionary measures to ensure patient safety.

• Assess bone mineral density: monitor for osteoporosis risk.
• Evaluate liver function: check hepatic enzymes before and during therapy.
• Screen for cardiovascular risk: monitor blood pressure and lipid profile.
• Avoid use in premenopausal women: drug is ineffective without ovarian suppression.
• Store at ambient temperature: keep below 25 °C in the original pack, protect from moisture.

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

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce plasma levels of letrozole.
• Concurrent use with tamoxifen: antagonistic effect on estrogen suppression.
• Estrogen replacement therapy: counteracts intended action of letrozole.

Moderate Interactions (Monitor Closely)

• CYP2A6 inhibitors (e.g., fluvoxamine): may increase letrozole exposure.
• Anticoagulants (e.g., warfarin): monitor INR as hormonal changes may affect coagulation.
• Statins: observe for potential additive liver enzyme elevations.