What is Letrozole?
Letrozole is a medication primarily used to treat breast cancer in postmenopausal women. It belongs to a class of drugs known as aromatase inhibitors, which work by decreasing the amount of estrogen produced in the body. This reduction in estrogen can slow the growth of certain types of breast tumors that require estrogen to grow.
Mechanism of Action
Letrozole inhibits the enzyme aromatase, which is responsible for the conversion of androgens to estrogens. By lowering estrogen levels, letrozole stimulates the hypothalamus and pituitary gland to produce more FSH, thereby promoting follicular development and ovulation.Indications for Letrozole in Gynecology
The primary indication for letrozole in gynecology is for
ovulation induction in women with anovulatory infertility, especially those with PCOS. It may also be used in cases where clomiphene citrate has failed to induce ovulation or in women who experience side effects from clomiphene.
Dosage and Administration
For ovulation induction, letrozole is typically administered in a dose of 2.5 to 5 mg daily for five days, usually starting on day 3 or day 5 of the menstrual cycle. The dosage may be adjusted based on the patient's response, monitored by ultrasound and hormone levels.Effectiveness of Letrozole
Studies have shown that letrozole is as effective, if not more so, than clomiphene citrate for
inducing ovulation. It is often preferred in women with PCOS due to its better side effect profile and higher pregnancy rates. Additionally, letrozole is associated with a lower risk of multiple pregnancies compared to clomiphene.
Side Effects and Risks
Common side effects of letrozole include hot flashes, fatigue, dizziness, and headache. Less commonly, it can cause joint pain, nausea, and weight gain. Though rare, there is a potential risk of ovarian hyperstimulation syndrome (OHSS), which can be serious.Contraindications
Letrozole should not be used in premenopausal women with normal ovarian function, pregnant women, or those who are breastfeeding. It is also contraindicated in patients with known hypersensitivity to letrozole or any of its components.Monitoring and Follow-Up
Patients undergoing treatment with letrozole for ovulation induction should be closely monitored with
transvaginal ultrasound to assess follicular development and endometrial thickness. Hormone levels, especially estradiol, may also be measured. Follow-up visits are crucial to adjust dosage and address any side effects.
Conclusion
Letrozole is a valuable medication in the field of gynecology, particularly for ovulation induction in women with PCOS and other ovulatory disorders. Its effectiveness, coupled with a favorable side effect profile, makes it a preferred choice for many clinicians. However, careful monitoring and appropriate patient selection are essential to optimize outcomes and minimize risks.
