Clomiphene (trademark Clomid) is used to treat infertility in women who do not ovulate. It is the most prescribed drug for ovulation induction. It can reverse anovulation (no ovulation) and oligoovulation (irregular ovulation).
Clomid is a selective estrogen receptor modulator (SERM) or estrogen-blocking drug. It is used as an ovarian stimulator by inhibiting the negative feedback of estrogen at the hypothalamus (part of brain).
As the negative feedback of estrogen is inhibited, the hypothalamus secretes the hormone GnRh which in turn stimulates the anterior pituitary gland to secrete LH and FSH (hormones) which help achieve ovulation.
The typical starting dosage of Clomid is 50 milligrams a day for 5 days, starting around 3-5 days after the start of the menstrual period. Most women will ovulate within 5 to 10 days after taking Clomid.
If no ovulation is achieved during the first cycle, dosage is usually increased to 100 mg per day for the second cycle and possibly 150 mg per day for the third cycle.
80% of women taking Clomid will successfully ovulate, and about 10% of them will conceive per cycle.
Since Chlomid treatment is usually prescribed for up to 6 months, up to 60% of the women who achieved ovulation will become pregnant.
Therefore, the overall effectiveness of Chlomid treatment is about 50%.
The most common side effect is reversible ovarian enlargement ( > 10% of people ).
Less common effects (< 10% of people) include visual symptoms like blurred vision, headaches, hot flashes, light sensitivity, abnormal uterine bleeding, abdominal discomfort.
Like many fertility drugs, Clomid can lead to multiple ovulation, hence increasing the chance of twins (10% of births instead of ~1% in the general population).
A team led by Frank Palopoli at William S. Merrell Chemical Company synthesized clomifene in 1956; and filed a patent which issued in November 1959.
Clomid has been FDA approved and marketed since 1967. It is available in most pharmacies and stores such as Costco or Walmart at low cost.