Cyproterone acetate came into the medical landscape in the 1960s, developed from efforts to curb the effects of androgens in certain conditions. Researchers in Europe first recognized its ability to block testosterone and similar hormones, using bench chemistry that relied heavily on trial, error, and careful observation. The compound found its purpose in both men and women, with early papers quickly circulating its uses for prostate cancer and severe cases of acne and hirsutism. As a person fascinated by medical history, it strikes me how quickly new medicines can move from a lab curiosity to a trusted standard, shaped by the real struggles of the people who need them most.
Cyproterone acetate sits on the shelf as a synthetic steroidal anti-androgen with added progestogenic features. The molecule shows up as a white or slightly yellow powder, and it refuses to dissolve in water but responds better in organic solvents. It has a reputation for slowing down the action of male hormones, which means it fits into therapies for conditions that depend on those androgens. This includes not just prostate issues, but also problems like excessive hair growth on the face and body in women, and it forms part of some contraceptive combinations as well. If you have spent any time in hospital pharmacies or around endocrinology practices, the name rings familiar—it’s a mainstay for these sorts of hormone-driven cases.
Looking at its structure, cyproterone acetate holds the chemical formula C24H29ClO4 and offers a molecular weight of just over 416 g/mol. A chlorine atom on its A-ring makes a big difference in its behavior. Its melting point hovers between 210°C to 213°C, and you won’t see it budge much at room temperature. No strong odor, stable if kept away from light and moisture, and packed in amber glass containers, this compound demands respect in storage. Chemists handling it note its low solubility in water but better performance in acetone, chloroform, and ethanol. Careful handling and accurate measurement are part of everyday routines where this molecule appears.
When packaged for pharmacies or clinics, cyproterone acetate must carry detailed labeling. Purity levels run over 98%. Each batch gets checked for contamination, with certificates outlining residual solvents and heavy metals. Most regulatory bodies insist on labeling that names the strength per tablet or ml, the route of administration, dosage instructions, expiration date, storage requirements, and batch information. Those standards don’t just exist for regulation—they protect patients, and having read enough incident reports over the years, I know clear labeling makes all the difference.
Synthesis usually starts with 17α-hydroxyprogesterone derivatives, which take to chemical modification well. The acetate group gets added through an acylation process, then the molecule’s A-ring is chlorinated at a precise spot. Every chemist working on this process learns to watch for byproducts—cleanliness of the reaction, attention to isolation steps, and careful washing with solvents is the difference between a high-quality batch and a waste of time and resources. Analytical tests like HPLC and NMR scanning confirm purity. These aren’t just technicalities; the results directly determine if the drug reaches the people who need it safely.
Cyproterone acetate invites a short but crucial list of chemical modifications, mainly focused on its progestogenic and anti-androgenic effects. Each new analog brings subtle shifts in potency or side effect profile. For example, removing the chlorine atom drastically weakens its activity, while adjustments to the acetate group tweak absorption and metabolism. In my time reading clinical pharmacology journals, the impact of small molecular changes can’t be overstated. These tweaks feed back directly into patient outcomes—sometimes a simple switch in synthesis yields a version with fewer mood effects or better effectiveness in a specific disorder.
Cyproterone acetate goes by a host of names: Androcur, Cyprostat, Procur, and SH-810. Healthcare professionals often use the generic name, especially in academic discussion, but a quick trip to almost any clinic in Europe turns up the brand names. Knowing these synonyms matters—prescription errors come from simple name confusion, and as anyone who’s fielded a worried parent’s call over pharmacy substitutions can tell you, clarity in communication wins every time.
Handling cyproterone acetate inside the pharmacy, the clinic, and laboratories demands good protective practices. Gloves, eye protection, and careful handwashing go hand in hand with handling guidelines. Inhalation or direct contact stays off-limits, not just for occupational safety but for environmental care, too. Needle-stick injuries involving this compound cause more than a few headaches for hospital safety teams, and spill kits in oncology wards are stocked to deal with cytotoxins like this. Regulatory bodies require detailed logs for amounts, distribution, and disposal—more than just red tape, it forms the front line in avoiding accidental exposure.
Cyproterone acetate’s impact stretches from urology to dermatology, and across into gender-affirming care. It remains a first-line choice for metastatic prostate cancer, where the aim is to starve tumors of the androgens they need. Skin clinics write countless prescriptions for severe acne resistant to other options and for women living with polycystic ovary syndrome who struggle with unwanted hair growth. In transgender medicine, its ability to suppress testosterone supports hormone regimens. Having spent time in multidisciplinary team meetings talking through treatment options, the importance of flexibility with this drug stands out—it offers hope in situations where other treatments just don’t fit.
Academic efforts keep pushing cyproterone acetate’s boundaries. Scientists continue to investigate new derivatives, aiming to hold onto the benefits while cutting away side effects like liver stress or mood swings. Recent studies probe how lower doses might still work for acne or hair problems, meaning fewer risks for patients down the line. Pharmacogenomics—tailoring the drug to a person’s unique genetic makeup—surfaces more and more in the research I follow, especially in reproductive health. Each advance reflects how careful observation in the clinic feeds real-world data back to the researchers, driving steady improvement.
Toxicology data on cyproterone acetate highlights a list of concerns that every prescribing doctor must keep close. Liver function stands at the front of the queue—reports of rare but severe liver toxicity shaped prescribing rules over the last decade. Psychiatric side effects, including depressive moods, became more noticeable as the pool of patients grew. Animal studies showed dose-dependent effects on fertility, which pushed both patients and physicians to talk through long-term plans before starting therapy. Regulatory agencies responded with safety updates, encouraging close bloodwork monitoring and careful patient selection before a prescription ever goes out the door.
Cyproterone acetate’s future in medicine looks tightly linked to two forces: innovation in hormone therapies and deeper understanding of long-term safety. The pipeline shows new compounds aiming to keep its benefits with less risk. Digital health tools, like remote liver monitoring and genetic risk calculators, promise earlier warnings about side effects and smarter follow-up care. In regulatory halls, conversations focus on balancing patient access with up-to-date safety data, keeping both old and new users protected. From the perspective of someone who has witnessed the evolution of standards in hormone care, the work ahead means more tailored medicine, stronger patient education, and more transparency in risk management.
Cyproterone acetate might sound like a name reserved for a chemistry lab, but in the real world, many people encounter it for very practical reasons. This medication helps those navigating hormone-driven health challenges. Doctors use it to block the hormone testosterone, which shows up in a range of treatments related to reproductive health, gender affirmation, and certain cancers.
I’ve seen friends and patients face hormone-driven skin issues. For women prone to acne or hair loss, the body tends to pump out more male hormones—testosterone and its cousins. This is where cyproterone acetate steps in. It quiets down those hormones. Birth control pills containing cyproterone acetate have helped many regulate excessive hair growth, secure clearer skin, and regain confidence. In the gender-affirming care space, it’s a cornerstone for transgender women. By reducing testosterone, this drug supports physical changes that align with their identity. This isn’t just medication; for many, it’s freedom from body dysphoria and social anxiety.
Prostate cancer feeds on testosterone. Many men facing this disease want to slow it down, draw out their time with family and friends, and stay active. That’s where cyproterone acetate comes in. By turning down the testosterone, doctors can give patients another way to manage the disease. Cyproterone acetate often sits alongside other medications in the toolkit, but it’s been around for decades and proven reliable for symptom control, especially for those experiencing hormone-driven sexual urges tied to their cancer diagnosis. These combinations give patients an opportunity to reclaim a bit of normalcy.
No one walks into a pharmacy expecting miracles without warnings. Cyproterone acetate can bring side effects. Liver health sometimes takes a hit; fatigue and mood swings become common talking points with loved ones. Young women, especially those with polycystic ovary syndrome (PCOS), use the drug to temper symptoms, but regular check-ins become necessary because of the risks to the liver. Blood clots also raise concerns. European health agencies have sounded alarms over rare but real connections between this medication and certain types of brain tumors, especially at high doses or over long stretches. From experience, open and honest conversations with a doctor really make a difference before starting something long-term.
This isn’t a medicine to pick up without a real plan. Cyproterone acetate asks for routine lab work, close follow-up, and honest updates between patient and medical team. Women on this drug for birth control, transgender women in the middle of transition, or men fighting cancer—all deserve to know their risks and should not be afraid to ask questions. Doctors with deep experience in endocrinology or oncology bring real-world knowledge to these decisions, giving people the best shot at balancing benefits with side effects. If someone is juggling two or three other medications, extra caution makes sense. Even the most proven treatments hold risk if ignored for too long.
Medicine keeps evolving. Research teams around the globe keep testing alternative anti-androgens and hormone blockers to see which ones work better, cause fewer side effects, or cost less money. That said, for many patients, cyproterone acetate stays in the conversation because it delivers vital changes—physical, emotional, and social—that let people step more fully into their lives. Responsible use and up-to-date information make it a tool that serves everyone better, no matter their diagnosis.
Cyproterone acetate usually comes up in conversations about hormone-related conditions. People might hear about it for treating prostate troubles in men or controlling symptoms of conditions like polycystic ovary syndrome (PCOS) and acne in women. Knowing the kinds of side effects to expect can help someone keep an eye on their health and talk honestly with their doctor if concerns pop up.
Many folks on cyproterone acetate mention having less energy. Days can feel slower, and there’s a sense that usual activities drain more effort. This tiredness can be more than an off day—it can drag on, especially in the first couple months. Some of it comes from the way this drug adjusts hormone activity, which can throw off everything from motivation to mood.
Doctors recognize that mood swings and feelings like depression show up more in people using cyproterone acetate. I have chatted with people who found themselves sad or irritable for no clear reason after starting it. Science backs up those stories: By shifting testosterone and estrogen levels, cyproterone acetate can upset emotional balance. A 2020 review in the journal Cancers pointed out that emotional struggles are common enough that friends and family should keep an eye open and provide support.
Some people on cyproterone acetate start noticing changes around their waistline. Extra pounds tend to sneak up, often connected to sluggish metabolism and fluid retention. People sometimes report bigger appetites, too. The body can start holding on to water, and clothes get tighter. Diabetes experts point out that weight gain not only adds to frustration but can also bump up risk for other health issues down the road.
Changes in sex drive are among the most commonly reported side effects. Men might notice erections come less often, and interest in sex can dip. These shifts can surprise patients since they might not realize hormones change so quickly. With long-term use, some men experience breast swelling or tenderness. Women with high testosterone levels might see a drop in facial hair or oily skin, but menstrual cycle changes, like irregularity or missing periods, also show up regularly.
Liver health occasionally takes a hit with this drug. Common blood tests give early warning signs, and yellowing of the eyes needs a doctor’s attention right away. Less common, but still important, are blood clots—signaled by swelling or pain in the legs. Both symptoms warrant urgent medical care.
Tackling these side effects begins with awareness. Regular blood tests and open check-ins with the care team catch small problems before they grow. For mood symptoms and fatigue, some patients benefit from counseling or exercise routines. Open conversations can clear up expectations and help patients weigh risks against improvements in their condition. Every person reacts differently, so knowing what to watch out for gives people power to protect their own well-being.
Cyproterone acetate touches many body systems, so reading up and asking questions helps people stay informed. Back-and-forth with experienced doctors brings real answers to individual concerns. With the right support, patients can make choices that fit their life and health goals.
Facing hormone-driven health problems makes daily life harder. Cyproterone acetate enters the picture as a key option for folks dealing with conditions like acne, certain forms of hair loss, prostate troubles, and some gender-affirming care. It doesn’t simply plug a gap—used right, it addresses real symptoms that affect self-esteem and comfort. Yet, as with many medicines, there’s a right way and a wrong way to use it.
Years working in health writing have shown me how often good intentions get derailed without concrete instructions. Unlike antibiotics or painkillers picked up from the drugstore, cyproterone acetate comes with specific steps and timing that reduce risks. According to research published by the European Medicines Agency, improper use has led to liver problems and even shifts in mood. Skipping regular check-ins or adjusting the dose on your own risks more harm than most realize.
Doctors usually prescribe cyproterone acetate in precise amounts. For individuals assigned male at birth facing prostate issues or seeking gender-affirming hormone therapy, a health professional often pairs this medication with estrogens for a balanced effect. People dealing with skin concerns or excessive hair growth might get much smaller doses, sometimes combined with birth control pills. Timing can make a difference—many instructions call for the pill to be taken after meals, alongside water, to reduce stomach trouble.
Skipping doses or taking more than told rarely works out. Cyproterone acetate affects hormone levels, which play a role in energy, motivation, and even blood clotting. Over the years, I’ve seen reports and patient stories where simple mistakes led to dizziness, headaches, and for some, serious blood-related problems. The European Society of Endocrinology points out that long-term or high-level use without ongoing blood tests doesn’t just raise flags in theory—patients have landed in hospitals because side effects went unnoticed.
Sharing the same prescription across family or friends, thinking “one size fits all,” stirs up trouble. Age, organ health, other medications, and even diet affect how cyproterone acetate gets processed. Real life doesn’t follow textbook rules. A person in their twenties responds differently than someone older with a heart condition. Heavy drinkers and smokers face extra traps, as their bodies break down hormones in unpredictable ways.
Real trust builds with open medical guidance. Anyone starting on cyproterone acetate deserves regular updates—liver function tests, blood checks, even mental health tracking form part of a smart routine. Pharmacies play their own part in reminding patients about timing or potential red flags like shortness of breath, leg pain, or even sudden mood changes.
Education helps more than scare tactics. Doctors giving detailed explanations about the “why” behind dosing schedules instead of rattling off rules see better results. Clinics that use follow-up calls or digital reminders cut down on missed doses. Drug fact sheets, simple language, and an open line for questions close the gap between a prescription and actual success. At the end of the day, cyproterone acetate can make a real difference when used with intention, information, and regular expert input.
Cyproterone acetate plays a central role in hormone therapy for a wide range of medical concerns, from acne and severe hirsutism to prostate issues and gender-affirming care. Still, not every patient should consider this medication. I’ve followed cases where rushing straight to Cyproterone led to regrettable outcomes. Listening to bodies and histories means protecting lives.
Liver toxicity turns up often with cyproterone acetate. Those with current or past liver problems—think hepatitis, cirrhosis, or masses—face higher risk for severe complications, including liver failure and jaundice. In my practice, screening liver enzymes and reviewing viral histories becomes routine before even discussing the drug. European safety updates warn that liver dysfunction can develop rapidly on this medication; a 2018 meta-analysis in the European Journal of Endocrinology showed nontrivial liver enzyme spikes among long-term users. Upper abdominal pain or new fatigue can’t get brushed off.
Cyproterone acetate can increase the risk for thromboembolism. Anyone who has had a blood clot, stroke, or pulmonary embolism sits in the danger zone. For women over 35 who smoke, combining cyproterone with estrogens throws risk even higher. I remember a patient with a family clotting disorder who suffered a sudden leg DVT weeks into therapy. Stories like that remind both prescribers and patients to dig deep into family history and consider safer alternatives.
The European Medicines Agency flagged meningioma cases in people using high-dose cyproterone. Even at moderate doses, the tumor risk creeps up. Imaging studies back this up: meningiomas increase in frequency among long-term users. Patients with previous meningioma diagnoses, or any symptoms pointing toward brain tumors—headaches, vision changes—should not start therapy. A neurologist I trust won’t clear this drug unless the benefit hugely outweighs the risk.
Pregnant women need to avoid cyproterone completely due to effects on developing reproductive organs. Breastfeeding mothers should steer clear too, since traces may reach infants. Prepubertal children require careful consideration, since the drug can alter normal sexual development. Most guidelines restrict use in these groups to rare scenarios under specialist supervision.
Hormone-dependent cancers, like certain breast tumors, react unpredictably to cyproterone. People with prostate cancer sometimes require this medication, but only after full risk assessment. Also, rare metabolic conditions—such as Dubin-Johnson or Rotor syndromes—reveal how nuanced prescribing has to be for anyone with a genetic liver quirk.
To keep risks in check, doctors run baseline blood panels, hormone tests, and thorough interviews before considering cyproterone acetate. Ongoing follow-up with regular liver checks and vigilance for neurological symptoms stands as standard procedure in places with tight health regulation. Anyone on this route needs open communication with their medical team, clear health goals, and immediate contact if new symptoms emerge.
Safer alternatives often exist. Spironolactone, GnRH analogues, or non-hormonal options give many patients similar results with fewer dangers. In my experience, the best outcomes come from informed choices, honest conversations, and frequent monitoring—avoiding shortcuts for any quick fix.
Cyproterone acetate rose to popularity as a medication dealing with hormone-driven problems, especially in the treatment of prostate cancer, severe acne, or hirsutism. It acts by blocking the body's effect of male hormones (androgens), which people living with these conditions know all too well can be life-altering. Doctors sometimes prescribe it alongside other medications, especially in more complex cases. That’s where the concern about drug interactions really kicks in.
Meds don't act in a vacuum. Start stacking prescriptions, and chemistry gets messy. Cyproterone acetate doesn’t just float through the bloodstream untouched. In the liver, enzymes chew it up, and that's the same spot countless other drugs break down. For people on lots of meds—think blood thinners, HIV treatments, or anti-seizure pills—unexpected side effects or dips in effectiveness aren’t out of the question.
One example: cyproterone acetate can make it harder for the liver to process drugs like warfarin and phenytoin. People taking warfarin to keep their blood thin and prevent clots know that small dosage changes mean big risks. Cyproterone acetate can also shake up how diabetes medicines act, sometimes throwing blood sugar off course. Doctors track these things with blood tests, but it’s not a one-size-fits-all situation.
Cyproterone acetate often mixes with ethinylestradiol in some birth control pills. Combining hormones brings extra layers of complexity. Some antibiotics or anti-epileptic drugs can dial down the effectiveness of hormonal birth control, risking unplanned pregnancies. The old advice to double up on protection during a course of something like rifampicin isn’t just scare tactics—real-life pregnancies happen.
Certain medications for anxiety or depression—especially those processed in the liver—can interact awkwardly with cyproterone acetate. Patients already navigating mood swings or psychological side effects often find changes in their hormone therapy can tip the balance in ways that feel anything but minor.
Many times, patients forget to mention herbal supplements or over-the-counter remedies they pick up at the grocery store. Even St. John’s Wort can mess with liver metabolism, and pharmacists see all too often how someone can get blindsided by a “natural” product making their prescription fluctuate.
Talking openly with doctors and pharmacists matters more than most realize. Keeping a current list of every medication—including supplements—can help spot interactions before they turn into emergencies. Ideally, every new prescription comes with a short huddle about possible side effects or red flags. Electronic health records help, but not every pharmacy system talks neatly to every hospital or clinic. Patients get the most help from professionals when they stay proactive, asking questions and following up after changes.
Long-term, more hospitals need smart systems to catch these interactions early. Some places have drug interaction alerts for prescribers, but these can get ignored if the list is too overwhelming or full of irrelevant flags. Streamlined, family-friendly medication counseling in plain language should show up everywhere, from primary care visits to specialty clinics. Pharmacists also deserve a bigger role as educators and partners, flagging issues before they start instead of after the fact.
| Names | |
| Preferred IUPAC name | 2a-Hydroxy-1a,2,9,15-tetramethyl-5-oxo-13-chloro-17-acetoxy-17a-pregna-4,6-diene-3-carboxylic acid |
| Other names |
Androcur
Cyprostat Cyprone Cyproteronum Procur Ciproterona CPA |
| Pronunciation | /saɪˌproʊtəroʊn əˈsiːteɪt/ |
| Preferred IUPAC name | (2R,3Z,6R,8R,9S,10R,13S,14S,17S)-17-Acetoxy-6-chloro-2-hydroxy-10,13-dimethyl-3-(2-oxopropylidene)-2,6,7,8,9,11,12,14,15,16-decahydro-1H-cyclopenta[a]phenanthren-17-yl acetate |
| Other names |
Androcur
Androcur Depot Cyprostat Cyproteronacetat CPA |
| Pronunciation | /saɪˌproʊtəˈroʊn əˈsiːteɪt/ |
| Identifiers | |
| CAS Number | 427-51-0 |
| Beilstein Reference | 136216 |
| ChEBI | CHEBI:2880 |
| ChEMBL | CHEMBL1426 |
| ChemSpider | 1932 |
| DrugBank | DB04839 |
| ECHA InfoCard | 100.038.747 |
| EC Number | 200-203-3 |
| Gmelin Reference | 77713 |
| KEGG | D00278 |
| MeSH | D003562 |
| PubChem CID | 2723 |
| RTECS number | GZ1251000 |
| UNII | 7Z5C8Y7XYB |
| UN number | UN2811 |
| CAS Number | 427-51-0 |
| Beilstein Reference | 1462303 |
| ChEBI | CHEBI:4052 |
| ChEMBL | CHEMBL1231 |
| ChemSpider | 3873 |
| DrugBank | DB04839 |
| ECHA InfoCard | 100.002.351 |
| EC Number | 206-639-3 |
| Gmelin Reference | 228220 |
| KEGG | D03584 |
| MeSH | D003562 |
| PubChem CID | 61911 |
| RTECS number | GZ2066000 |
| UNII | E4HSF53709 |
| UN number | UN2811 |
| Properties | |
| Chemical formula | C24H29ClO4 |
| Molar mass | 416.932 g/mol |
| Appearance | white or almost white crystalline powder |
| Odor | Odorless |
| Density | 1.27 g/cm³ |
| Solubility in water | Insoluble in water |
| log P | 3.2 |
| Vapor pressure | 9.84E-12 mmHg at 25°C |
| Acidity (pKa) | 12.94 |
| Basicity (pKb) | 12.65 |
| Magnetic susceptibility (χ) | -1200.0e-6 cm³/mol |
| Refractive index (nD) | 1.543 |
| Viscosity | Oily liquid |
| Dipole moment | 2.88 D |
| Chemical formula | C24H29ClO4 |
| Molar mass | 416.915 g/mol |
| Appearance | White or almost white, odourless, crystalline powder |
| Odor | Odorless |
| Density | 1.2 g/cm³ |
| Solubility in water | Slightly soluble in water |
| log P | 3.6 |
| Vapor pressure | 6.58E-12 mmHg at 25°C |
| Acidity (pKa) | 12.65 |
| Basicity (pKb) | 2.90 |
| Magnetic susceptibility (χ) | -5.7×10^-7 |
| Refractive index (nD) | 1.566 |
| Viscosity | Viscous liquid |
| Dipole moment | 3.62 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 576.6 J·mol⁻¹·K⁻¹ |
| Std molar entropy (S⦵298) | 325.9 J·mol⁻¹·K⁻¹ |
| Std enthalpy of combustion (ΔcH⦵298) | -11095 kJ/mol |
| Pharmacology | |
| ATC code | G03HA01 |
| ATC code | G03HA01 |
| Hazards | |
| Main hazards | Toxic if swallowed. Suspected of causing cancer. Suspected of damaging fertility or the unborn child. Causes damage to organs through prolonged or repeated exposure. |
| GHS labelling | GHS05, GHS07, GHS08 |
| Pictograms | GHS06, GHS08 |
| Signal word | Warning |
| Hazard statements | H360: May damage fertility or the unborn child. |
| Precautionary statements | Use personal protective equipment as required. Avoid release to the environment. IF exposed or concerned: Get medical advice/attention. Dispose of contents/container in accordance with local/regional/national/international regulations. |
| NFPA 704 (fire diamond) | NFPA 704: 2-1-0 |
| Flash point | > 218.6 °C |
| Lethal dose or concentration | LD50 (rat, oral): 6000 mg/kg |
| LD50 (median dose) | LD50 (median dose): Mouse (oral) 2329 mg/kg |
| NIOSH | Not Listed |
| PEL (Permissible) | PEL (Permissible) for Cyproterone Acetate: Not established |
| REL (Recommended) | 25–100 mg daily |
| Main hazards | May cause harm to unborn children, suspected of causing cancer, may cause liver damage, may impair fertility. |
| GHS labelling | GHS07, GHS08 |
| Pictograms | GHS06, GHS08 |
| Signal word | Warning |
| Hazard statements | H360fd: May damage fertility. May damage the unborn child. |
| Precautionary statements | P201, P202, P281, P308+P313, P405, P501 |
| NFPA 704 (fire diamond) | Health: 2, Flammability: 1, Instability: 0, Special: - |
| Flash point | > 207.2 °C |
| Autoignition temperature | 400°C |
| Lethal dose or concentration | LD50 (rat, oral): 8000 mg/kg |
| LD50 (median dose) | LD50 (median dose): Rat oral LD50 2000 mg/kg |
| PEL (Permissible) | PEL (Permissible Exposure Limit) for Cyproterone Acetate: Not established |
| REL (Recommended) | 50–100 mg daily |
| IDLH (Immediate danger) | Not established |
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