Overview
Cyproterone acetate is a synthetic steroid with antiandrogenic and progestogenic properties, primarily used to treat conditions related to androgen excess. It acts as a competitive antagonist at androgen receptors and suppresses gonadotropin secretion, reducing testosterone production.
Mechanism of Action
Competitive antagonist at androgen receptors (blocks dihydrotestosterone binding). Also has strong progestogenic activity that suppresses gonadotropin (LH/FSH) secretion from the pituitary, leading to reduced testicular testosterone production. Mild glucocorticoid activity may contribute to adrenal suppression at high doses.
Indications
- Prostate cancer (palliative treatment)
- Severe hirsutism in women
- Acne vulgaris (severe cases in women)
- Androgenetic alopecia in women
- Reduction of sex drive in men with hypersexuality or paraphilias (off-label in some regions)
Dosage
Varies by indication: Prostate cancer: 100-300 mg daily. Hirsutism/acne: 2-100 mg daily (typically 2-50 mg) in cyclic regimen with estrogen. Always follow prescribing physician's instructions.
Contraindications
- Liver disease (active or history)
- Dubin-Johnson/Rotor syndromes
- History of meningioma
- Severe chronic depression
- Thromboembolic disorders
- Pregnancy
- Lactation
- Known hypersensitivity
Side Effects
- Fatigue
- Weight changes
- Gynecomastia
- Loss of libido
- Hepatotoxicity
- Thromboembolism
- Depression
- Nausea
- Headache
- Adrenal insufficiency
- Glucose intolerance
Interactions
- Enzyme inducers (rifampicin, phenytoin) reduce efficacy
- Alcohol increases hepatotoxicity risk
- Other hepatotoxic drugs
- Oral anticoagulants (monitor)
- Insulin/oral hypoglycemics (adjust dose)