Anti-Androgenic Drugs

ANTI-ANDROGENIC DRUGS


ANTI-ANDROGENIC DRUGS

  • MOA: Acts by inhibiting synthesis, activation or action of androgens.

Drug groups:

I) Steroid synthesis inhibitors:

  • Drugs included: Ketoconazole & Abiraterone.

Ia) Ketoconazole:

  • MOA:
    • Inhibits synthesis of adrenal & gonadal hormones.
    • On prolonged use – Serious toxicity limits usage in treatment of prostatic carcinoma.
  • Adverse effects:
    • Cause gynaecomastia – Due to increase in estradiol:testosterone ratio.

Ib) Abiraterone:

  • Orally active prodrug.
  • MOA: 
    • Acts by inhibiting 17-α-hydroxylase & 17, 20-lyase.
  • Reduces synthesis of both cortisol & androgens.
  • Approved for castration-resistant refractory prostate cancer.

II) 5-α reductase inhibitors:

  • 5-α reductase –
    • Most testosterone actions are mediated by its conversion to DHT by 5-α reductase.
    • Actions mediated include growth of prostate, male pattern baldness & hirsutism in females.
  • Drugs: Finasteride & dutasteride.
  • Uses: BHP treatment, male pattern baldness & hirsutism – By reducing DHT production.

III) Androgen receptor inhibitors:

  • MOA: 
    • Acts as antagonists of androgen receptors.
  • Drugs
    • Cyproterone, cyproterone acetate, flutamide, bicalutamide, enzalutamide, nilutamide.
  • Cyproterone acetate:
    • Marked progestational activity.
    • A component of contraceptive pills.
    • Inhibits feedback enhancement of LH & FSH.
  • Uses: 
    • Hirsutism treatment.
    • Treatment of prostatic carcinoma.
  • Flutamide:
    • Cause gynaecomastia & reversible liver damage.
    • Combined with GnRH agonists (like leuprolide) – To reduce initial flare-up reaction.

IV) Aldosterone antagonist:

  • Spironolactone:
    • Competes with DHT for its receptor.
    • Used for hirsutism treatment & in heart failure.

Exam Important

  • Anti-androgenic drugs act by inhibiting synthesis, activation or action of androgens.
  • Anti-androgenic drugsinclude steroid synthesis inhibitors (ketoconazole & abiraterone), 5-α reductase inhibitors (finasteride & dutasteride), androgen receptor inhibitors (Cyproterone, cyproterone acetate, flutamide, bicalutamide, enzalutamide, nilutamide), aldosterone antagonist (Spironolactone).
  • Ketoconazole inhibits synthesis of adrenal & gonadal hormones.
  • Ketoconazole can cause gynaecomastia, due to increase in estradiol:testosterone ratio.
  • Abiraterone is orally active prodrug, acts by inhibiting 17-α-hydroxylase & 17, 20-lyase.Abiraterone reduces synthesis of both cortisol & androgens.
  • Abiraterone is approved for castration-resistant refractory prostate cancer.
  • 5-α reductase enzyme mediates most testosterone actions by its conversion to DHT by 5-α reductase.
  • Finasteride & dutasteride used for  5-α reductase inhibitors.
  • Finasteride & dutasteride are useful for BHP treatment, male pattern baldness & hirsutism, by reducing DHT production.
  • Cyproterone acetate is a component of contraceptive pills with marked progestational activity.
  • Flutamide cause gynaecomastia & reversible liver damage.
  • Flutamide is combined with GnRH agonists (like leuprolide, treduce initial flare-up reaction.
  • Spironolactone is used for hirsutism treatment & heart failure.
Don’t Forget to Solve all the previous Year Question asked on ANTI-ANDROGENIC DRUGS

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