Letrozole Stada (Letrozole)

Letrozole acts on estrogen‑dependent pathways and is indicated for the following conditions:

• Hormone receptor‑positive breast cancer (postmenopausal): Reduces tumor progression by decreasing estrogen production.
• Ovulation induction in anovulatory women: Facilitates follicular development by lowering estrogen feedback.
• Endometriosis‑related pain (off‑label): Alleviates symptoms through suppression of estrogen‑driven tissue growth.

• Letrozole selectively and reversibly binds to the aromatase enzyme, inhibiting the conversion of androstenedione and testosterone to estrone and estradiol. By blocking peripheral estrogen synthesis, systemic estrogen concentrations decline, depriving estrogen‑dependent tumor cells of a growth stimulus while preserving other hormonal pathways. The inhibition is dose‑dependent and results in a marked reduction of circulating estradiol levels, which is the primary driver of hormone‑sensitive breast cancer growth.

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

Common Side Effects

• Hot flashes: Sudden feeling of warmth, often with sweating.
• Joint and muscle pain: Arthralgia or myalgia affecting daily activities.
• Fatigue: Persistent tiredness not relieved by rest.
• Nausea: Mild to moderate upset stomach.

Serious or Rare Side Effects

• Severe liver injury: Elevated enzymes or hepatitis.
• Bone fractures: Increased risk due to lowered estrogen.
• Deep vein thrombosis or pulmonary embolism: Blood clots in veins or lungs.
• Allergic reactions: Rash, swelling, or anaphylaxis.

When prescribing Letrozole, clinicians should observe the following precautions to ensure patient safety.

• Bone health monitoring: Assess bone mineral density regularly due to risk of osteoporosis.
• Liver function assessment: Check hepatic enzymes before initiation and periodically.
• Cardiovascular risk evaluation: Review history of thromboembolic events.
• Pregnancy avoidance: Contraindicated in pregnancy; ensure effective contraception.
• Drug interaction review: Avoid concurrent use with estrogen‑containing therapies.
• Store at ambient temperature: Keep below 25 °C in original packaging, protect from moisture.

Letrozole interacts with several medicines; awareness of the interaction level guides clinical management.

Major Interactions (Avoid)

• Estrogen‑containing hormone therapy: Counters Letrozole’s effect.
• Tamoxifen: May reduce therapeutic benefit when combined.
• Strong CYP3A4 inhibitors (e.g., ketoconazole): Increase Letrozole plasma levels.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): May lower effectiveness.
• Anticoagulants (e.g., warfarin): Potential alteration of INR.
• SSRIs and SNRIs: May affect hot‑flash management.