Letrozole (brand name Femara) is a medication primarily used to treat hormone receptor-positive breast cancer in postmenopausal women. It is also commonly used as a fertility treatment, particularly for women with ovulatory disorders such as polycystic ovary syndrome (PCOS). It is an aromatase inhibitor that works by lowering estrogen levels, which in turn:

• Slow or stop the growth of hormone-sensitive tumors.

• Stimulates the pituitary gland to release more follicle-stimulating hormone (FSH). This increase in FSH promotes ovulation.

Uses of Letrozole

1. Breast Cancer Treatment – Used as an adjuvant therapy for early-stage hormone receptor-positive breast cancer or for advanced/metastatic breast cancer.

2. Fertility Treatment – Often prescribed off-label to induce ovulation in women with conditions like polycystic ovary syndrome (PCOS) or unexplained infertility.

3. Hormone Suppression – Used in transgender hormone therapy and bodybuilding to manage estrogen levels.

Letrozole for Infertility Treatment

1. Indications:

   • First-line treatment for ovulation induction, especially in PCOS.

   • Used in unexplained infertility.

   • Can be prescribed for women who do not respond to Clomid (clomiphene citrate).

   • Sometimes used in ovarian stimulation for intrauterine insemination (IUI) or in-vitro fertilization (IVF) protocols.

2. Mechanism of Action:

   • Blocks aromatase, reducing estrogen levels.

   • Lower estrogen leads to increased FSH, stimulating follicular development.

   • Helps produce a stronger ovulatory response than Clomid with lower risks of multiple pregnancies.

3. Dosage & Administration:

   • Typically, 2.5–7.5 mg daily for five days (starting on cycle day 2, 3, 4, or 5).

   • Ovulation usually occurs about 7 days after the last dose.

4. Success Rates:

   • Higher ovulation rates in women with PCOS compared to Clomid.

   • Pregnancy rates are comparable or better than Clomid with fewer side effects.

   • Lower risk of multiple pregnancies compared to Clomid.

5. Side Effects:

   • Fatigue, dizziness, headaches.

   • Hot flashes.

   • Mild nausea.

   • Less risk of thin uterine lining than Clomid.

6. Contraindications & Risks:

   • Not recommended in pregnant women (can cause fetal harm).

   • May not be suitable for women with certain liver disorders.

   • May cause bone thinning (osteoporosis), so bone density monitoring is recommended.

   • Can lead to cholesterol changes; lipid levels should be monitored.

Letrozole (Femara)