Products
Clomiphene was commercially available in tablet form (Serophene, Clomid). It was approved in many countries since 1967 and is currently no longer available. Drugs containing the active ingredient can be imported from abroad.
Structure and properties
Clomiphene (C26H28ClNO, Mr = 405.95 g/mol) is a nonsteroidal triphenylethylene derivative that exists as an unequal mixture of the – and -isomers (enclomiphene and zuclomiphene). It is present in drugs as clomiphene dihydrogen citrate, a white to pale yellow crystalline powder that is sparingly soluble in water. Clomiphene is closely structurally related to tamoxifen (Nolvadex, generics).
Effects
Clomiphene (ATC G03GB02) exerts both antiestrogenic and weak estrogenic properties. It attenuates the negative feedback of endogenous estrogens. This stimulates the secretion of GnRH (gonadotropin-releasing hormone) in the hypothalamus. The result is increased pituitary release of the gonadotropins FSH and LH, which promotes follicular maturation and triggers ovulation. Clomiphene has a long half-life of up to 5 days. Under the drug, the probability of multiple pregnancy is increased (about 10% twins, 1% triplets).
Indications
To induce ovulation in women with infertility due to failure to ovulate, for example in polycystic ovary syndrome.
Dosage
According to the SmPC. The tablets are usually taken once daily for 5 days starting on the 5th day after menstruation (5th to 9th day of cycle). If pregnancy occurs, the tablets must not be administered again. The duration of therapy should not usually exceed three months.
Abuse
Clomiphene can be abused as a doping agent and is prohibited outside of and during athletic competition. It is most often taken after the end of a steroid cycle (abuse of anabolic steroids).
Contraindications
Full precautions can be found in the drug label.
Interactions
Interactions with other drugs are not known to date.
Adverse effects
The most common possible adverse effects include:
- Enlargement of the ovaries
- Hot flashes
- Nausea and vomiting, abdominal pain.
- Headache, restlessness
- Visual disturbances, such as a decrease in visual acuity, blurred vision, double vision, flashes of light and sensitivity to light.
