Antiandrogen – Effects, Uses and Side Effects
Antiandrogens are substances that block or reduce the effects of male sex hormones (androgens). They are used to treat prostate cancer, acne, hirsutism, and more.
Wissenswertes über "Antiandrogen"
Antiandrogens are substances that block or reduce the effects of male sex hormones (androgens). They are used to treat prostate cancer, acne, hirsutism, and more.
What Is an Antiandrogen?
Antiandrogens are a class of substances that reduce or completely block the biological effects of androgens – the male sex hormones such as testosterone and dihydrotestosterone (DHT). They either bind to androgen receptors and prevent activation, or they inhibit the production and conversion of androgens in the body. Antiandrogens are widely used in medicine and hormone therapy for a variety of conditions.
Mechanism of Action
Androgens exert their effects by binding to specific androgen receptors inside target cells. Antiandrogens work by competing with androgens at these receptor sites or by interfering with androgen production. There are two main mechanisms:
- Receptor antagonists: These substances bind to the androgen receptor without activating it, thereby preventing androgens from triggering their usual cellular effects (e.g., bicalutamide, flutamide, spironolactone).
- Inhibitors of androgen synthesis or conversion: These substances block enzymes involved in the production or activation of androgens (e.g., 5-alpha-reductase inhibitors such as finasteride, or GnRH analogues that suppress testosterone production in the testes).
Medical Uses
Prostate Cancer
Antiandrogens are a cornerstone of treatment for hormone-sensitive prostate cancer. Because the growth of prostate cancer cells is often driven by androgens, blocking these hormones can slow or halt tumor progression. Antiandrogens are frequently used in combination with surgical or medical castration (GnRH analogues).
Benign Prostatic Hyperplasia (BPH)
For benign enlargement of the prostate (BPH), 5-alpha-reductase inhibitors such as finasteride or dutasteride are used. They block the conversion of testosterone into the more potent dihydrotestosterone (DHT), thereby reducing prostate volume and relieving urinary symptoms.
Acne and Seborrhea
Androgens stimulate sebaceous glands in the skin. In androgen-dependent acne or excessive sebum production (seborrhea), antiandrogens – particularly in women – can significantly improve symptoms. Commonly used agents include cyproterone acetate (often found in combined oral contraceptives) and spironolactone.
Hirsutism
Hirsutism refers to excessive hair growth in women following a male pattern. Because this condition is often caused by elevated androgen levels or increased androgen sensitivity, antiandrogens can reduce unwanted hair growth in affected areas.
Androgenetic Alopecia
In androgen-dependent hair loss (male or female pattern baldness), 5-alpha-reductase inhibitors reduce the effect of DHT on hair follicles, slowing or stopping hair loss progression.
Gender-Affirming Hormone Therapy
As part of gender-affirming care for transgender women (male-to-female), antiandrogens are used to suppress the effects of testosterone and support a feminizing hormone regimen.
Polycystic Ovary Syndrome (PCOS)
Women with PCOS often have elevated androgen levels, leading to acne, hirsutism, and irregular menstrual cycles. Antiandrogens can help manage these symptoms effectively.
Key Antiandrogen Agents
- Bicalutamide – non-steroidal androgen receptor antagonist, primarily used in prostate cancer
- Flutamide – non-steroidal androgen receptor antagonist, used in prostate cancer and hirsutism
- Cyproterone acetate – steroidal androgen receptor antagonist, used for acne, hirsutism, and prostate cancer
- Spironolactone – aldosterone antagonist with antiandrogenic properties, used for acne and hirsutism
- Finasteride / Dutasteride – 5-alpha-reductase inhibitors, used for BPH and hair loss
- Enzalutamide – next-generation androgen receptor antagonist, used in castration-resistant prostate cancer
Side Effects
The side effects of antiandrogens depend on the specific agent and dosage. Commonly reported adverse effects include:
- Decreased libido and sexual dysfunction (in men)
- Gynecomastia (breast tissue growth in men)
- Hot flashes
- Fatigue and tiredness
- Reduced bone density (increased risk of osteoporosis with long-term use)
- Liver function abnormalities (particularly with flutamide)
- Mood changes and depressive symptoms
In women, antiandrogenic therapy is often well tolerated; however, antiandrogens are contraindicated during pregnancy as they may interfere with the development of male fetuses.
Important Notes
Antiandrogen therapy should always be initiated and monitored by a qualified healthcare professional. Regular check-ups – including blood counts, liver function tests, and hormone levels – are essential during treatment. Patients should not adjust their dose or discontinue therapy without consulting their doctor.
References
- Attard G. et al.: Prostate cancer. The Lancet, 387(10013):70-82, 2016. DOI: 10.1016/S0140-6736(14)61947-4
- Katzung B.G., Trevor A.J.: Basic and Clinical Pharmacology, 15th edition. McGraw-Hill Education, 2021.
- Rosenfield R.L., Ehrmann D.A.: The Pathogenesis of Polycystic Ovary Syndrome (PCOS). Endocrine Reviews, 37(5):467-520, 2016. DOI: 10.1210/er.2015-1104
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Related search terms: Antiandrogen + Antiandrogens + Anti-Androgen + Anti-Androgens