Letrozole Generics [uk] (Letrozole)

Letrozole is used in the management of estrogen‑dependent breast cancer, acting on the hormonal pathway that drives tumor growth.

• Hormone receptor‑positive breast cancer (postmenopausal): Reduces tumor recurrence by lowering estrogen levels.
• Adjuvant therapy after surgery (postmenopausal): Decreases risk of disease progression when combined with other treatments.
• Metastatic breast cancer (postmenopausal): Improves disease control by suppressing estrogen‑driven tumor growth.

• Letrozole selectively inhibits the aromatase enzyme, which converts adrenal and ovarian androgens into estrogens. By blocking this peripheral conversion, systemic estrogen concentrations fall, depriving estrogen‑dependent tumor cells of a growth stimulus and thereby slowing or halting disease progression.

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

Common Side Effects

• Hot flashes: transient episodes of increased skin temperature.
• Joint and muscle pain: mild to moderate arthralgia or myalgia.
• Fatigue: general tiredness affecting daily activities.
• Nausea: occasional upset stomach.

Serious or Rare Side Effects

• Osteoporosis: decreased bone mineral density leading to fractures.
• Severe liver injury: marked elevation of hepatic enzymes or hepatitis.
• Cardiovascular events: rare cases of thrombosis or myocardial infarction.

When prescribing Letrozole, clinicians should consider several safety and handling precautions.

• Assess bone health: baseline densitometry recommended due to risk of osteoporosis.
• Monitor liver function: periodic tests advised because of potential hepatotoxicity.
• Evaluate cardiovascular risk: consider history of thrombosis before initiation.
• Avoid use in pregnancy: drug is contraindicated in women of childbearing potential unless effective contraception is used.
• Store at ambient temperature: keep below 25 °C in original container, protect from moisture and light.

Letrozole can interact with other medicines, altering its effectiveness or increasing toxicity.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampicin, carbamazepine): may reduce letrozole plasma concentrations.
• Tamoxifen: concurrent use may antagonize therapeutic effect.

Moderate Interactions (Monitor Closely)

• Anticoagulants (warfarin): may increase bleeding risk; monitor INR.
• SSRIs (e.g., fluoxetine): potential for additive hot‑flash reduction; observe symptoms.
• Hormone replacement therapy: may diminish letrozole’s estrogen‑lowering action.