Uses of Cyproterone
Cyproterone acetate is primarily used as an antiandrogen medication for treating prostate cancer, hirsutism, acne, and as part of hormone therapy for transgender women due to its ability to block androgen receptors and suppress testosterone production.
Mechanism of Action
Cyproterone acetate works through two main mechanisms:
- Acts as a steroidal antiandrogen that inhibits androgen binding to receptors in target tissues 1
- Has progestational properties that create feedback inhibition of pituitary LHRH release, suppressing testosterone production 1, 2
Clinical Applications
1. Prostate Cancer
- Used to treat prostate cancer by blocking the effects of androgens that stimulate cancer growth 1
- Prevents acute flare of disease during initial treatment with GnRH agonists 2
- Typically administered at 200 mg/day to prevent disease flare and reduce hot flushes associated with GnRH agonist therapy or orchiectomy 2
- For monotherapy in prostate cancer, dosages of 250 mg/day or greater are generally required 2
2. Hirsutism and Hyperandrogenic Skin Conditions
- Effectively treats hirsutism with success rates of approximately 85% 3
- Used for moderate to severe acne related to androgen-sensitivity (with or without seborrhea) in women of reproductive age 4
- Often combined with ethinyl estradiol (35 μg) for treating hyperandrogenic skin symptoms 4
- Particularly effective for women with polycystic ovarian syndrome (PCOS) experiencing hyperandrogenic skin symptoms 4
3. Male Hypogonadism
- Listed as a drug that can cause male hypogonadism through its progestogenic effects 5
- Can block androgen receptors, leading to drug-induced AR blockage 5
4. Hormone Management in Cancer Survivors
- Used for vasomotor symptoms (hot flashes) in men with prostate cancer who are on androgen deprivation therapy (ADT) 5
Important Considerations
Dosing
- For prostate cancer: 200-250 mg/day 2
- For hirsutism/acne in women: Usually 2 mg combined with 35 μg ethinyl estradiol 4
- For sexual disorders in men: 100-200 mg daily orally or 300 mg weekly intramuscularly 6
Side Effects
- Liver toxicity with long-term use (potentially fatal) 1
- Gynecomastia in approximately 20% of male patients 6
- Tiredness, lack of drive, listlessness, and depressive moods 6
- In women, side effects similar to those of estrogen-containing contraceptives 3
Availability
- Available in Canada and Europe, but not approved in the United States 1
Treatment Duration
- For hirsutism: Therapeutic response requires a long-term approach 4
- For sexual disorders: Effects on libido and erectile function begin after approximately 14 days of treatment 6
Monitoring
- Regular liver function tests are essential during treatment 1
- Monitoring of androgen levels may be helpful but does not necessarily predict treatment success 3
Cyproterone acetate represents an important therapeutic option for conditions requiring androgen suppression, though its use must be balanced against potential side effects, particularly hepatotoxicity with long-term administration.