Clomifene

Clomifene (INN) or clomiphene (USAN and former BAN) or Clomid or Clomifert is a selective estrogen receptor modulator (SERM), used mainly in female infertility due to anovulation (e.g. due to polycystic ovary syndrome). In some countries, it is also registered for use in men. Clomiphene citrate is marketed under various trade names including Clomid, Serophene, Milophene, etc.

Mode of action
Clomifene acts by inhibiting the action of estrogen on the gonadotrope cells in the anterior pituitary gland. In response to low estrogen levels, follicle-stimulating hormone (FSH) release is increased, leading to a higher rate of ovulation and hence pregnancy.

Clomifene can lead to multiple ovulation, and hence increasing the chance of twins. In comparison to purified FSH, the rate of ovarian hyperstimulation syndrome is low. There may be an increased risk of ovarian cancer and weight gain.

Chemistry
Clomifene is a diastereomeric mixture of two geometric isomers, enclomifene (E-clomifene) and zuclomifene (Z-clomifene).

Adverse effects
Common adverse drug reactions associated with the use of clomifene (≥1% of patients) include: hot flashes, abdominal discomfort, visual blurring, and/or reversible ovarian enlargement and cyst formation. Infrequent adverse effects (0.1–1% of patients) include: abnormal uterine bleeding, nausea, and/or vomiting. Rare adverse effects (<0.1% of patients) include: reversible alopecia and/or ovarian hyperstimulation syndrome. In some cases, patients have developed palinopsia.

Use in bodybuilding
Clomifene is commonly used by male anabolic steroid users to bind the estrogen receptors in their bodies, thereby blocking the effects of estrogen, i.e., gynecomastia. It also restores the body's natural production of testosterone. It is commonly used as a "recovery drug" and taken toward the end of a steroid cycle.