Androgen antagonists are a group of pharmacological agents that block the effects of male sex hormones at the receptor level or via pituitary regulatory pathways. Based on their structure, they are divided into nonsteroidal competitive agents and steroid progesterone derivatives, which are used in oncology, dermatology, and neuropsychiatric practice.
Bicalutamide RegimenPrescribed once daily.
Flutamide RegimenRequires administration 3 times daily.
Triple MechanismCyproterone acts at central, peripheral, and receptor levels.
Dose RangeCyproterone ranges from 2 mg/day for acne up to 300 mg/day in oncology.
Nonsteroidal Competitive Antagonists
Nonsteroidal competitive blockers include flutamide (Flutamide) and bicalutamide (Bicalutamide).
Mechanism of action: These drugs competitively bind to androgen receptors, preventing endogenous androgens from interacting with them.
Clinical application:
The primary indication is prostate cancer.
In oncology, these agents are used in combination with GnRH analogs.
Dosage regimens:
Flutamide (Flutamide) is administered 3 times daily.
Bicalutamide (Bicalutamide) is administered once daily.
Steroid Drugs (Progesterone Derivatives)
A representative of steroid antiandrogens is cyproterone (Cyproterone), which is of progestational nature.
Cyproterone pharmacodynamics is characterized by a triple mechanism of action:
Receptor component: Acts as a partial androgen receptor agonist with antiandrogen activity.
Central component: Suppresses the production and secretion of pituitary gonadotropic hormones.
Peripheral component: Reduces the expression of androgen effects directly in target tissues.
Indications for Use
The clinical spectrum of antiandrogen therapy varies between male and female patients.
In men:
Reduction of pathologically elevated sexual drive (hypersexuality).
Prostate cancer (in obligatory combination with GnRH analogs).
In women:
Correction and treatment of acne.
Elimination of manifestations of masculinization.
Dosage Dependence on Therapeutic Goals
Cyproterone is characterized by a significant spread in dosages depending on the clinical goal:
Dermatology (acne treatment): Minimum dosage is used — 2 mg daily.
Behavioral correction (hypersexuality): Intermediate dose is used — 100 mg daily.
Oncology (prostate cancer): Maximum dose is prescribed — 300 mg daily.
Mnemonic
Remember the frequency of nonsteroidal agents: Bicalutamide — Briefly once a day, Flutamide — Frequently 3 times a day. Cyproterone dosage increases with the severity of the goal: 2 mg (acne) → 100 mg (behavior) → 300 mg (oncology).
Frequently asked questions
What side effects are characteristic of nonsteroidal androgen antagonists?
Nonsteroidal androgen antagonists are characterized by the development of arterial hypertension.
Bicalutamide (Bicalutamide) exhibits a pressor effect, causing elevated blood pressure in cancer patients.
Long-term use of nonsteroidal antiandrogens is also associated with an overall increase in side effect frequency, which must be considered when evaluating minimal survival benefits in prostate cancer treatment.
What are the contraindications to prescribing cyproterone?
Long-term use of synthetic progestins in adrenogenital syndrome is contraindicated because suppressing gonadotropins against the background of already suppressed ovarian function is undesirable.
What is the main difference in administration schedules between flutamide and bicalutamide?
Flutamide (Flutamide) must be taken 3 times a day, whereas bicalutamide (Bicalutamide) is prescribed only once a day.
What are the components of cyproterone's triple mechanism of action?
Cyproterone (Cyproterone) acts as a partial receptor agonist with antiandrogen activity, centrally inhibits the secretion of pituitary gonadotropins, and peripherally decreases androgen effects in tissues.
Under what conditions are androgen antagonists prescribed to women?
In women, indications for these agents include the treatment of acne and symptoms of masculinization.
How does the dose of cyproterone depend on the indications?
The dosage is determined by the goal of therapy: a minimum dose of 2 mg/day is used in dermatology for acne, an intermediate dose of 100 mg/day for hypersexuality correction, and a maximum dose of 300 mg/day in oncology for prostate cancer.
Go deeper
Competitive blockade of androgen receptors by flutamide and bicalutamide
Use of nonsteroidal antiandrogen and GnRH analog combinations in prostate cancer
Triple pharmacodynamic mechanism of cyproterone
Cyproterone dosing scale: from dermatological to oncological doses
Indications for antiandrogen therapy in men with hypersexuality