Letrozol Ratiopharm (Letrozole)

Letrozole is used in the management of estrogen‑dependent breast cancer, targeting tumors that rely on peripheral estrogen synthesis.

• Hormone receptor‑positive breast cancer in postmenopausal women: Administered as adjuvant therapy to lower recurrence and improve disease‑free survival.
• Early‑stage breast cancer: Used after surgery to reduce the risk of progression and support long‑term remission.
• Advanced or metastatic breast cancer: Employed to control tumor growth and extend survival in patients with estrogen‑driven disease.

• Letrozole selectively and reversibly inhibits the aromatase enzyme, a non‑steroidal inhibitor that blocks the conversion of androstenedione and testosterone to estrone and estradiol in peripheral tissues. By reducing systemic estrogen levels, it deprives estrogen‑dependent tumor cells of a growth stimulus, thereby slowing or halting cancer progression. The inhibition is dose‑dependent and leads to a marked decrease in circulating estrogen within days, which is the primary therapeutic effect in estrogen‑sensitive malignancies.

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

Common Side Effects

• Hot flashes: sudden feeling of warmth, often with sweating.
• Joint or muscle pain: aches in bones, joints, or muscles.
• Fatigue: persistent tiredness or lack of energy.
• Nausea: feeling of queasiness or urge to vomit.
• Headache: mild to moderate head pain.
• Sweating: increased perspiration.

Serious or Rare Side Effects

• Severe osteoporosis or bone fractures: significant loss of bone density leading to fractures.
• Deep vein thrombosis or pulmonary embolism: blood clots in veins or lungs.
• Liver function abnormalities: elevated enzymes indicating hepatic stress.

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

• Bone health monitoring: assess bone mineral density and consider calcium/vitamin D supplementation.
• Cardiovascular risk assessment: evaluate history of thromboembolic events before initiating therapy.
• Liver function testing: perform baseline and periodic liver enzyme tests.
• Drug interactions: review concomitant medications that may affect estrogen levels.
• Pregnancy and lactation: contraindicated; avoid use in pregnant or breastfeeding women.
• Store at ambient temperature: keep tablets in original container, protect from moisture and light.

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

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampicin, carbamazepine): may reduce plasma concentrations.
• Estrogen‑containing therapies (e.g., hormone replacement therapy): antagonize therapeutic effect.

Moderate Interactions (Monitor Closely)

• Antifungal agents (e.g., ketoconazole): may increase exposure.
• Anticoagulants (e.g., warfarin): potential for altered INR, monitor coagulation.
• Selective serotonin reuptake inhibitors (e.g., fluoxetine): may affect metabolism.