Klomifeeni

Klomifeeni, also known as clomiphene citrate, is a selective estrogen receptor modulator (SERM) used primarily to treat infertility caused by anovulation. It is a mixture of geometric isomers that binds to estrogen receptors and alters hormonal feedback in the hypothalamic-pituitary-gonadal axis.

Mechanism of action involves antagonism of estrogen receptors in the hypothalamus, which reduces estrogenic negative feedback. This leads to increased release of gonadotropin-releasing hormone (GnRH), and subsequently higher circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The rise in LH and FSH can stimulate follicular development and ovulation in women who do not ovulate regularly.

Typical use includes oral administration, often starting with 50 mg taken once daily for five days early in the menstrual cycle. If ovulation does not occur, the dose may be increased in subsequent cycles, up to commonly 100–150 mg per day, under medical supervision. The treatment duration is usually several cycles, and not all patients respond. It is sometimes used in select cases of polycystic ovary syndrome and other anovulatory disorders.

Efficacy and safety considerations vary. Ovulation may be induced in a substantial subset of women, but pregnancy rates per cycle are influenced by age and underlying fertility factors. Side effects can include hot flashes, bloating, breast tenderness, mood changes, and nausea. Ovarian enlargement and, rarely, ovarian hyperstimulation syndrome or visual disturbances can occur. Contraindications include pregnancy, liver disease, and estrogen-dependent tumors. Clomifeeni should be used under medical supervision, with monitoring of response and ongoing assessment of risks and benefits.