Antiandrogen — oncology-focused definition
Antiandrogens are drugs that block the action of androgens (male sex hormones, primarily testosterone and dihydrotestosterone) at their receptor, thereby inhibiting androgen-driven tumor growth.
Mechanism of Action:
- Bind to the androgen receptor (AR) on target cells, preventing activation by natural androgens.
- Some antiandrogens also reduce AR nuclear translocation or cofactor recruitment, inhibiting transcription of androgen-responsive genes.
Clinical relevance in oncology:
- Primary use: Prostate cancer, especially androgen-sensitive or metastatic prostate cancer.
- Drug examples
| Class | Drug Examples | Notes / Use |
|---|---|---|
| Non-steroidal antiandrogens | Flutamide, Bicalutamide, Enzalutamide, Apalutamide | Often combined with LHRH agonists/antagonists (chemical castration) |
| Steroidal antiandrogens | Cyproterone acetate, Nilutamide | Less commonly used; also have some progestogenic effects |
| LHRH (GnRH) analogs / antagonists | Leuprolide, Goserelin, Degarelix | Indirectly reduce androgen production (not receptor blockers, but part of androgen deprivation therapy) |
- Therapeutic goal: Slow tumor growth, reduce PSA levels, and manage metastatic disease.
- Adverse effects: Hot flashes, fatigue, decreased libido, gynecomastia, osteoporosis, cardiovascular risk.
Key takeaway:
Antiandrogens block androgen receptor signaling, making them a cornerstone of hormone therapy for prostate cancer, often in combination with other forms of androgen deprivation therapy for maximum efficacy.
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