Clomifene is an oral medication used to treat certain types of infertility in women who do not ovulate and is often known by brand names such as Clomid or Serophene. The medication is a first-line treatment for conditions like polycystic ovary syndrome (PCOS) that cause anovulation, the failure of the ovary to release an egg. It works by stimulating the body’s own hormones to trigger ovulation.
The Mechanism of Action
Clomifene is classified as a selective estrogen receptor modulator (SERM). Its primary function is to interact with estrogen receptors in the hypothalamus. The medication temporarily blocks these receptors, which tricks the brain into perceiving a low level of estrogen. This perceived deficiency prompts the pituitary gland to increase its output of two important hormones.
The pituitary gland responds by releasing more Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH). FSH travels to the ovaries and stimulates the development of one or more follicles, which are small sacs that contain immature eggs. As the follicles grow, they produce estrogen, and the rising estrogen levels prepare the uterine lining for a potential pregnancy.
A rapid surge in LH levels typically occurs mid-cycle and acts as the direct trigger for ovulation. This surge causes the most mature follicle to rupture and release its egg from the ovary. The released egg is then available for fertilization.
The Treatment Process
Clomifene can also be used to make menstrual cycles more predictable to improve the timing of intercourse or insemination. A good candidate for this treatment has a body mass index (BMI) between 19 and 30, as weight can influence success rates.
Treatment begins early in the menstrual cycle, often starting on the second, third, fourth, or fifth day after a period begins. The standard starting dose is typically 50mg, taken orally as a tablet once a day for five consecutive days. Taking the tablet at the same time each day is recommended to maintain consistent levels of the medication in the body.
Throughout the treatment cycle, a healthcare provider monitors the woman’s response. Monitoring may involve transvaginal ultrasounds to track the number and size of developing follicles and to measure the thickness of the uterine lining. Blood tests to measure hormone levels, particularly progesterone, are often performed around day 21 of the cycle to confirm if ovulation has occurred. If ovulation does not happen at the initial dose, the dosage may be increased in subsequent cycles.
Potential Side Effects and Associated Risks
Common mild side effects include hot flashes, bloating, mood swings, and mild abdominal or pelvic discomfort. These symptoms are temporary and resolve after the five-day course of medication is completed.
Less common, but more serious, are visual disturbances, such as blurring or seeing spots. If these vision changes occur, it is advised to stop taking the medication and contact a doctor immediately. Driving or operating machinery should be avoided until it is clear how the medication affects you, as it can cause drowsiness or dizziness.
There are two main risks associated with clomifene treatment. The first is an increased chance of a multiple gestation pregnancy. Because the medication stimulates the ovaries to develop follicles, it is possible for more than one egg to be released and fertilized. The other risk is Ovarian Hyperstimulation Syndrome (OHSS), a condition where the ovaries become swollen and painful; however, this is an uncommon occurrence with clomifene.
Off-Label Applications
Beyond its primary use for female infertility, clomifene is sometimes prescribed for off-label purposes. The most frequent off-label application is in treating certain types of male infertility. This usage is considered “off-label” because it has not been officially approved for this purpose by regulatory agencies.
In men, clomifene functions similarly by blocking estrogen receptors in the brain, which can lead the pituitary gland to release more LH and FSH. These hormones then stimulate the testes to produce higher levels of testosterone and to increase sperm production. This treatment is typically managed by a specialist in reproductive medicine.