Cyproterone Acetate: Uses, Side Effects, and Safety Tips

Cyproterone acetate (CPA) is an antiandrogen and progestin used to lower effects of testosterone. People may get it for severe acne or hirsutism in women, as part of transgender hormone therapy, or in some prostate cancer treatments. This page explains what CPA does, the risks you need to watch for, and simple safety steps you can follow with your clinician.

How it's used and who might take it

Doctors prescribe CPA when reducing male hormones helps a medical problem. For women, that can mean less facial hair, fewer acne flares, or better control of hormonal symptoms. For trans women, CPA is often added to reduce testosterone while estrogen does other work. In prostate cancer, higher CPA doses have been used to lower cancer growth driven by androgens. Your doctor will explain why CPA fits your situation and how it compares to other options.

People take different strengths and schedules depending on the condition. That’s one reason never to copy someone else’s dose. If you’re prescribed CPA, follow the plan your clinician gives and ask questions about timing and interactions with other meds.

Side effects, risks, and what to monitor

Common side effects include tiredness, weight changes, mood shifts, and lowered sex drive. Some people notice breast tenderness or changes in liver tests. CPA has been linked with liver injury in rare cases, so doctors often order liver function tests before starting and during treatment. There’s also evidence tying long-term, high-dose CPA to an increased risk of developing meningioma (a usually benign brain tumor). That risk seems dose-related, so regular follow-up matters.

Mood changes and depression can occur. If you or someone close to you spots new or worsening low mood, anxiety, or thoughts of self-harm, contact your healthcare provider right away. Also tell your doctor about any headaches, vision changes, or seizures because those may need immediate checks.

CPA is not safe in pregnancy. Women who can become pregnant should use reliable contraception while taking CPA and for the time advised by their doctor after stopping it. Discuss fertility plans with your clinician before starting CPA.

Other medicines can interact with CPA. Always give your prescriber a full list of drugs, supplements, and herbal products you use. Don’t stop or change doses without medical advice—sudden changes can cause problems.

If CPA isn’t right for you, there are alternatives such as spironolactone, bicalutamide, or surgical options depending on the reason for treatment. Each alternative has its own pros and cons, so ask for a comparison that fits your goals and medical history.

Practical tips: get baseline labs (including liver tests), schedule regular follow-ups, report mood or neurological symptoms fast, and never share medication. If you have questions about effects or risks, bring them up at your next visit. Clear communication keeps treatment safer and more effective.