Non-steroidal competitive antagonists
Non-steroidal competitive blockers include flutamide (Flutamide) and bicalutamide (Bicalutamide).
Mechanism of action: the drugs bind competitively to androgen receptors, preventing interaction with endogenous androgens.
Clinical use:
- The primary indication is prostate cancer.
- In oncology, these agents are used in combination with gonadotropin-releasing hormone analogues.
Dosing regimens:
- Flutamide (Flutamide) is prescribed 3 times a day.
- Bicalutamide (Bicalutamide) is used once a day.
Steroid drugs (progesterone derivatives)
A representative of steroid antiandrogens is cyproterone (Cyproterone), which is progesterone-derived.
The pharmacodynamics of cyproterone is characterized by a triple mechanism of action:
- Receptor component: acts as a partial agonist of androgen receptors with antiandrogen activity.
- Central component: suppresses the production and secretion of pituitary gonadotropic hormones.
- Peripheral component: reduces the manifestation of androgen effects directly in target tissues.
Indications for use
The spectrum of clinical use of antiandrogen agents differs between male and female patients.
- In men:
- Reduction of pathologically elevated sexual desire (hypersexuality).
- Prostate cancer (in mandatory combination with gonadotropin-releasing hormone analogues).
- In women:
- Correction and treatment of acne.
- Elimination of manifestations of masculinization.
Dependence of dosing on therapy goals
Cyproterone is characterized by a significant spread in used doses depending on the clinical goal of administration:
- Dermatology (acne treatment): the minimum dosage is used — 2 mg daily.
- Behavioral correction (hypersexuality): the medium dose is used — 100 mg daily.
- Oncology (prostate cancer): the maximum dose is prescribed — 300 mg daily.
Briefly: answers to topical questions
What adverse effects are typical for non-steroidal androgen antagonists?
Non-steroidal androgen antagonists are characterized by the development of arterial hypertension.
- Bicalutamide (Bicalutamide) has a pressor effect, causing an increase in blood pressure in cancer patients.
Long-term administration of non-steroidal antiandrogens is also associated with an overall increase in the frequency of adverse effects, which must be considered when evaluating the minimal survival benefit in prostate cancer treatment.
What are the contraindications to prescribing cyproterone?
The source indicates that long-term use of synthetic progestins in adrenogenital syndrome is contraindicated, as gonadotropin suppression is undesirable against the background of already suppressed ovarian function.
Remember the dosing frequency of non-steroidal agents: Bicalutamide — Briskly (once a day), Flutamide — Frequently 3 times a day. The dose of cyproterone increases with the severity of the goal: 2 mg (acne) → 100 mg (behavior) → 300 mg (oncology).
Class and exam questions
What is the main difference in the administration regimen of 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 the triple mechanism of action of cyproterone?
Cyproterone (Cyproterone) works as a partial receptor agonist with antiandrogen activity, centrally inhibits the secretion of pituitary gonadotropic hormones, and peripherally reduces 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?
Dosage is determined by the goal of therapy: a minimum dose of 2 mg/day is used in dermatology for acne, a medium dose of 100 mg/day for the correction of hypersexuality, and a maximum dose of 300 mg/day in oncology for prostate cancer.
What else to study on this topic
- Competitive blockade of androgen receptors by flutamide and bicalutamide
- Use of a combination of non-steroidal antiandrogens and gonadotropin-releasing hormone analogues in prostate cancer
- Triple mechanism of cyproterone pharmacodynamics
- Cyproterone dosing scale: from dermatological to oncological doses
- Indications for antiandrogen therapy in men with hypersexuality
- Therapy for acne and masculinization in women
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