Letrafem (Letrozole)

Letrafem, an aromatase inhibitor, is indicated for conditions driven by estrogen synthesis.

• Hormone receptor‑positive breast cancer (postmenopausal): Reduces estrogen‑driven tumor growth and improves disease‑free survival.
• Advanced or metastatic breast cancer (postmenopausal): Delays disease progression when used as monotherapy or in combination with other agents.
• Adjuvant therapy after surgery (postmenopausal): Decreases the risk of cancer recurrence in patients who have undergone tumor resection.

• Letrozole reversibly binds to the aromatase enzyme, blocking the conversion of androgens to estrogens in peripheral tissues. This inhibition lowers circulating estrogen levels, depriving estrogen‑dependent tumor cells of a key growth stimulus and thereby slowing or halting cancer progression.

Letrozole may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Hot flashes: Sudden feeling of warmth, often with sweating.
• Arthralgia: Joint pain or stiffness.
• Fatigue: Persistent tiredness not relieved by rest.
• Nausea: Mild to moderate upset stomach.
• Headache: Pressure or throbbing pain in the head.
• Dizziness: Light‑headed sensation, especially when standing.

Serious or Rare Side Effects

• Severe liver injury: Jaundice, dark urine, elevated liver enzymes.
• Bone fracture: Increased risk due to reduced bone mineral density.
• Pulmonary embolism: Sudden shortness of breath, chest pain.
• Anaphylaxis: Rapid onset of swelling, hives, airway compromise.
• QT prolongation: Irregular heart rhythm that may lead to arrhythmia.

Before initiating Letrafem, clinicians should assess patient‑specific risk factors and monitor for potential complications.

• Bone health monitoring: Perform baseline and periodic bone mineral density scans.
• Liver function testing: Check hepatic enzymes prior to therapy and during treatment.
• Cardiovascular assessment: Evaluate for history of thromboembolic events.
• Drug interaction review: Identify concomitant medications that may alter letrozole metabolism.
• Pregnancy avoidance: Ensure effective contraception; letrozole is contraindicated in pregnancy.
• Store at ambient temperature (below 25°C): Keep in the original container, protect from moisture and direct sunlight.

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

Major Interactions (Avoid)

• Estrogen replacement therapy: Counteracts aromatase inhibition and reduces therapeutic benefit.
• Tamoxifen: Antagonistic effect on estrogen pathways, diminishing overall efficacy.
• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): Significantly lower plasma concentrations of letrozole.

Moderate Interactions (Monitor Closely)

• CYP2C19 inhibitors (e.g., fluconazole): May increase letrozole exposure modestly.
• Warfarin: Potential for enhanced anticoagulant effect; monitor INR.
• Statins (especially simvastatin): Slight increase in risk of muscle toxicity; observe for myalgia.