Pharmacology of cyproterone acetate

Cyproterone acetate (CPA), sold alone under the brand name Androcur or with ethinylestradiol (EE) as Diane or Diane-35 among others, is an antiandrogen and progestin medication used in the treatment of androgen-dependent conditions like acne, hirsutism, early puberty, and prostate cancer, as a component of feminizing hormone therapy for transgender women, and in birth control pills. It is formulated and used both alone and in combination with an estrogen and is available for use both by mouth and by injection into muscle.

Pharmacodynamics

CPA works by blocking and reducing the production of the androgen hormones, such as testosterone, that prostate cancer cells need to grow. It does this by binding to androgen receptors in the body which prevents the androgens from binding to their receptors and exerting their effects. CPA is also a potent progestin and hence can prevent ovulation in females.

Pharmacokinetics

After oral ingestion, CPA is well absorbed in the gut and widely distributed in the body. It is metabolized in the liver by the cytochrome P450 enzymes and to a lesser extent by hydrolysis. The metabolites of CPA are excreted in the urine and feces.

Side effects

The most common side effects of CPA include weight gain, fatigue, and breast tenderness. Less common side effects include depression, liver damage, and blood clots. CPA can also cause feminization in males, and if used during pregnancy, can harm the baby.

Interactions

CPA can interact with a number of other medications, including other hormones, certain antibiotics, and some antifungal drugs. It can also interfere with the results of certain laboratory tests.

See also

• List of progestogens
• List of antiandrogens