Can Cyproterone Acetate Be Prescribed?
Yes, cyproterone acetate (CA) can be prescribed in many countries, but it has significant contraindications and is not approved by the FDA for use in the United States. 1
Regulatory Status and Availability
Cyproterone acetate is available and prescribed in Europe and many other countries worldwide, but it is not FDA-approved and therefore not available for prescription in the United States. 1 The medication has been used clinically for over 25 years in countries where it is approved. 2
Approved Indications Where Available
In countries where CA is approved, it can be prescribed for:
- Prostate cancer treatment as monotherapy or in combination with other hormonal therapies 3, 4, 5
- Hidradenitis suppurativa in appropriate female patients, either as monotherapy for mild-to-moderate disease or in combination with other agents for more severe disease 3
- Polycystic ovary syndrome (PCOS) when combined with ethinyl estradiol 3
- Androgen-induced skin disorders including acne, seborrhea, hirsutism, and alopecia 2
- Sexual disorders in men requiring libido suppression 2
Absolute Contraindications
Cyproterone acetate cannot be prescribed in the following situations: 1
- Renal impairment
- Adrenal insufficiency
- High risk of arterial or venous thrombotic diseases
- Undiagnosed abnormal uterine bleeding
- Breast cancer
- Liver tumors or liver disease
- Co-administration with Hepatitis C drug combinations containing ombitasvir, paritaprevir/ritonavir, with or without dasabuvir
Specific Clinical Contraindications
For women with hereditary angioedema caused by C1 inhibitor deficiency (HAE-C1-INH), cyproterone acetate is specifically contraindicated because it has been reported to worsen HAE-C1-INH symptoms due to its potent antiandrogenic properties. 3
Thromboembolic Risk Considerations
When combined with ethinyl estradiol, CA-containing combined oral contraceptives carry an increased risk of venous thromboembolism (VTE) compared to some other progestins. 1 Epidemiologic studies show variable risk estimates, with some studies reporting up to a three-fold increase in VTE risk compared to levonorgestrel-containing contraceptives. 1 The highest VTE risk occurs during the first 6 months of use. 1
Dosing Considerations
When CA is prescribed (in countries where available):
- For prostate cancer: Typical doses range from 200-300 mg daily orally or 300 mg weekly intramuscularly 4, 2, 5
- For transgender women: Recent evidence suggests 10 mg daily is equally effective as higher doses (25-100 mg) for testosterone suppression while showing fewer side effects 6
- For hormonal therapy in females: Doses vary by indication, with lower doses used in combination products 3
Common Side Effects
Expected adverse effects include 4, 2:
- Impotence and loss of libido (when used in males)
- Gynecomastia and breast tenderness (less than 18% of patients)
- Tiredness, lack of drive, and depressive moods
- Cardiovascular complications (approximately 10% of treated men)
- Elevated prolactin concentrations (dose-dependent) 6
- Changes in liver enzyme concentrations 6
Clinical Pitfalls to Avoid
- Do not prescribe CA to patients with HAE-C1-INH as it can precipitate angioedema attacks 3
- Avoid in patients with thrombotic risk factors including smoking, obesity, and family history of VTE 1
- Stop CA at least 4 weeks before major surgery to reduce thromboembolism risk 1
- Use the lowest effective dose to minimize side effects, particularly prolactin elevation and lipid changes 6
- Monitor liver function as hepatotoxicity is a known risk 1