Estrogen blockers are chemical compounds that block the actions of estrogen. These drugs can work in a number of different ways, and they are used in several different applications, including in breast cancer treatment, where they are used to slow the growth of the tumor or to prevent recurrence. As with other medications that interact with hormones in the body, these medications should be used under the supervision of a healthcare professional.
There are a number of different kinds of estrogen blockers. Aromatase inhibitors, including vorozole, testolactone, and formestane, actually block the production of estrogen. Selective estrogen receptor modulators, such as tamoxifen, clomifene, and arzooxifene, are designed to block estrogen receptors, behaving slightly differently in different kinds of tissue. Antiestrogens also act to block estrogen receptors.
In the treatment of cancers, these drugs are used to slow the progress of the cancer. In the case of selective estrogen receptor modulators, they can also target specific estrogen receptors to deliver targeted therapy. Blockers, including clomiphene, are also sometimes used in infertility treatment, as they can assist some women who are having difficulty getting pregnant. These drugs are also used by some clinicians in the treatment of transgender children to essentially put puberty on hold until they are old enough to make decisions about whether or not they want to proceed with medical and surgical options.
Among body builders, some people promote the use of estrogen blockers because of the estrogenic effects of high levels of testosterone in the body. Testosterone is a precursor to estrogen, and aromatase inhibitors can be used to stop the body from forming excess estrogen, keeping levels in the body low. This practice has attracted controversy, especially when it is used for primarily cosmetic reasons and when people use pills and supplements sold without medical supervision.
There are a number of side effects associated with these medications. They can cause dizziness, headaches, sweating, hot flashes, and confusion. With the supervision of an endocrinologist, a patient can determine the appropriate dosage based on the situation and an acceptable threshold of side effects. The endocrinologist can also take regular blood samples to check on hormone levels in the blood while assessing the patient's overall health to confirm that the current drug regimen is still safe and functional for the patient.