Cyproterone (
cyproterone acetate) is a steroidal antiandrogenic agent that inhibits the action of adrenal and testicular
androgens on prostatic cells. Additionally, its progestogenic activity causes a centrally mediated reduction in testicular secretion of
androgens. Studies have demonstrated the effectiveness of
cyproterone monotherapy in patients with
prostate cancer, and for those in whom
orchiectomy is not an acceptable option
cyproterone may be a useful alternative. In addition, the
drug may be administered in combination with surgical or gonadotrophin-releasing
hormone (
GnRH) agonist-mediated
castration to ensure ablation of adrenal
androgens. However, the effectiveness of
cyproterone in combination with these forms of testicular
androgen deprivation remains to be fully established. Trials to date have not demonstrated prolonged survival in patients receiving the combination
therapy. Importantly, however,
cyproterone does prevent acute exacerbation of disease during initial treatment with a
GnRH agonist. Furthermore, combination
therapy tends to be associated with a lower incidence of hot flushes than
GnRH agonist-mediated or surgical
castration alone. Thus,
cyproterone 200 mg/day has proven efficacy in preventing acute flare of disease and reducing the incidence of hot flushes associated with
GnRH agonist
therapy or
orchiectomy. It may also facilitate maximal
androgen deprivation in patients receiving
GnRH agonist
therapy. If this
drug is used as monotherapy, dosages of 250 mg/day or greater will probably be required.