Article: Clomifene

Clomifene
Systematic (IUPAC) name
2-(4-(2-chloro-1,2-diphenylethenyl) phenoxy)-N,N-diethyl-ethanamine
Identifiers
CAS number	911-45-5
ATC code	G03GB02
PubChem	2800
DrugBank	APRD00880
Chemical data
Formula	C26H28ClNO
Mol. weight	406 or 598.10 (with citrate)
Pharmacokinetic data
Bioavailability	High (>90%)
Metabolism	Hepatic (with enterohepatic circulation)
Half life	5-7 days
Excretion	Mainly renal, some biliary
Therapeutic considerations
Pregnancy cat.	B3 (Au), X (U.S.)
Legal status	S4 (Au), POM (UK), ℞-only (U.S.)
Routes	50 mg tablets

Clomifene (INN) or clomiphene (USAN and former BAN) 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. Clomifene 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. "Sensing" 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 risk 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 racemic mixture of two geometric isomers, enclomifene (E-clomifene) and zuclomifene (Z-clomifene).

Enclomifene

Zuclomifene

Adverse effects

Common adverse drug reactions associated with the use of clomifene (≥1% of patients) include: hot flushes, 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.^[1]

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, ie gynecomastia. It also restores the bodies natural production of testosterone. It is commonly used as a "recovery drug" and taken toward the end of a steroid cycle.