clomifene

Clomifene, also known as clomiphene citrate or clomifene citrate, is a selective estrogen receptor modulator (SERM) used primarily to treat infertility due to anovulation in women. It is commonly prescribed for conditions such as polycystic ovary syndrome and other causes of lack of ovulation. The aim is to induce ovulation to enable pregnancy without resorting to injectable fertility treatments.

Clomifene acts by binding to estrogen receptors in the hypothalamus, reducing the negative feedback from endogenous estrogen. This increases the release of gonadotropin-releasing hormone (GnRH), which stimulates the pituitary to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The resulting follicular development and ovulation typically occur about one to two weeks after starting treatment, which is usually given as a five-day course.

Typical regimens begin with 50 mg once daily for five days early in the cycle (often days 3–7). If ovulation does not occur after one to three cycles, the dose may be increased to 100 mg daily for five days. Most guidelines limit clomifene therapy to around six cycles. Ovulation occurs in a majority of treated women, but pregnancy rates per cycle are modest and depend on age and underlying fertility issues.

Common side effects include hot flashes, breast tenderness, nausea, abdominal discomfort, and visual disturbances. Ovarian enlargement and, rarely, ovarian hyperstimulation syndrome can occur, especially when used with other fertility medications. There is an increased risk of multiple pregnancy.

Clomifene should not be used during pregnancy. Long-term use beyond six cycles is generally discouraged due to uncertain long-term safety and diminishing returns. It may be used off-label in men for certain forms of hypogonadism, but evidence is variable.