Antiandrogens are prescription medications used to lower the number of male sex hormones in the body. The medication is most commonly used by men to treat prostate cancer. People may also take antiandrogen drugs to treat acne, hair loss, polycystic ovarian syndrome (PCOS), gender dysphoria or hypersexuality.
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What Are Antiandrogens?
Antiandrogens prevent the body from producing androgens by blocking androgen receptors. The most notable androgen is testosterone. Other androgens include androstenedione, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEA-S).
Antiandrogen drugs can be used alone or in combination with other medications to decrease the number of androgens produced by the body.
Background and History
The first antiandrogens were developed in the 1960s. They are steroidal antiandrogens because their chemical structures are similar to steroids. They bind to the androgen receptor, but unlike nonsteroidal antiandrogens, they do not increase survival in prostate cancer.
The first nonsteroidal antiandrogen approved by the FDA for the treatment of prostate cancer was flutamide in 1989. It was originally developed to be used as an antibiotic in 1967. Clinical trials began in 1971 after it was discovered to have antiandrogenic properties. Other antiandrogens followed in the 1990s and 2000s, with apalutamide receiving FDA approval in 2018.
Medical Uses of Antiandrogens
Antiandrogens are used to treat many conditions, including:
- Prostate cancer in men
- Polycystic ovarian syndrome (PCOS) in women
- Hair loss
- Gender dysphoria
- Hypersexual disorder
Antiandrogens are most commonly used to treat prostate cancer. Since androgens help prostate cancer cells grow, blocking the receptors slows down the growth of the cancer. Antiandrogen therapy is used for other medical conditions, such as PCOS, hair loss and acne. These conditions are related to the body producing too much testosterone, and they can improve when testosterone in the body decreases.
Individuals with gender dysphoria may benefit from antiandrogens because the medication can prevent the body from experiencing puberty. Antiandrogens have been shown to prevent the body from developing the sexual characteristics associated with their sex at birth, such as breasts and testicles. Medication should be used in conjunction with therapy. The role of antiandrogen therapy after puberty is not well studied, but some antiandrogens for transgender individuals can be beneficial.
Hypersexuality, or sex addiction, may be treated with antiandrogens because the decrease in sex hormones generally causes a decrease in libido or sex drive. Because medication alone is rarely successful, it is recommended to be used in combination with therapy or counseling.
How Do Antiandrogens Work?
Antiandrogens work by blocking androgen receptors. Blocking these receptors prevents the body from producing androgens. Decreasing the production of androgens will decrease the number of male sex hormones in the body, specifically testosterone.
Both men and women produce androgens.
In men, androgens are known as the “steroid hormones” that lead to masculine characteristics and the development of the male reproductive system. It is rare for men to have too much testosterone or androgens. Low amounts of male sex hormones may result in a testosterone deficiency. Symptoms seen with low testosterone include mood disturbances, loss of muscle tone, poor sexual performance, increased body fat, osteoporosis, sleep problems and difficulty concentrating.
In women, androgens are converted to estrogen. They regulate the function of many organs in the body, including the reproductive system, bones, kidneys, liver and muscles. The estrogen that is made from androgens prevents bone loss and affects sex drive. When women produce too many androgens, they can develop acne, grow excess hair on the chin or upper lip and lose hair on the head. High levels of testosterone can lead to polycystic ovary syndrome (PCOS), diabetes, high cholesterol, high blood pressure and heart disease.
Women who have low androgen levels can also have health problems. Similar to men, women with low androgen levels may experience tiredness and low sex drive. They are also at risk for osteoporosis and fractures. Low androgen levels are more common in women who are about to go through menopause.
List of Antiandrogens
There are currently five antiandrogen pills approved by the United States Food and Drug Administration (FDA):
All of these medications are only FDA-approved for the treatment of prostate cancer. All other indications are considered to be “off label.” This means that the medical literature supports its use for other medical conditions, but it has not been approved by the FDA to be marketed for those indications. Generally, there is not enough information available to show that it is safe and effective for those medical conditions.
Some people may experience antiandrogenic effects when using the drug. Side effects of antiandrogen therapy include:
- Hot flashes
- Decreased libido (sex drive)
- Bone, back or muscle pain
- Muscle weakness or stiffness
- Swelling of the hands, legs, ankles or feet
- Increased blood pressure
- Increased risk of infection
- Trouble sleeping
- Dry skin
- Weight loss or weight gain
- Fatigue (tiredness)
- Bone fractures
- Gynecomastia (development of breasts)
- Liver dysfunction
Enzalutamide and apalutamide should be avoided in people who have a history of seizures. It was shown to increase the risk of seizures in people who are already at risk. At-risk people include those who take medications that lower the seizure threshold or people who have a history of head injury, stroke, Alzheimer’s disease, seizures or brain infection.
Drug interactions with antiandrogens depend on the specific antiandrogen. Bicalutamide may affect PT/INR in people taking warfarin (Coumadin). Enzalutamide and apalutamide interact with several drugs that are metabolized by certain enzymes produced by the liver. To prevent serious side effects, the antiandrogen or other drug may need dose adjustments.
Before taking an antiandrogen with other medications, ask your doctor or pharmacist to check for potential drug interactions. Some interactions will make the antiandrogen less effective, and others may cause serious side effects. The antiandrogen may also cause other drugs to be less effective or have severe side effects.
Taking Antiandrogens While Pregnant
Women should not take antiandrogens during pregnancy because these medications may cause birth defects. Women who need to take antiandrogens should consider taking an oral contraceptive or using another method of birth control to prevent pregnancy.
Women who are breastfeeding should avoid antiandrogens. Since antiandrogens are not FDA-approved for use in women, there is no information available on the effects in breastfed babies or milk production.
Get More Information on Antiandrogens
These resources can help you find out more about antiandrogens and their use in treating medical conditions:
Conditions such as gender dysphoria and hypersexual disorder can lead to substance use and addiction. If you or a loved one is suffering from an addiction or co-occurring mental health issue, The Recovery Village is here to help. Contact us today to find a treatment plan that can work well for you.
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American Cancer Society. “Hormone Therapy for Prostate Cancer.” July 18, 2018. Accessed June 17, 2019.
American Academy of Pediatrics. “Hormonal Treatment in Young People With Gender Dysphoria: A Systematic Review.” April 2018. Accessed June 17, 2019.
National Institutes of Health. “Treatments to Relieve Symptoms of PCOS.” January 31, 2017. Accessed June 17, 2019.
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DailyMed. “Flutamide- flutamide capsule.” July 20, 2014. Accessed June 18, 2019.
DailyMed. “Nilandron – nilutamide tablet.” August 31, 2018. Accessed June 18, 2019.
American Cancer Society. “Hormone Therapy for Prostate Cancer.” July 18, 2018. Accessed June 18, 2019.
National Cancer Institute. “Hormone Therapy for Prostate Cancer.” February 28, 2019. Accessed June 18, 2019.
Encyclopedia Britannica. “Antiandrogen.” Accessed June 18, 2019.
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