Cyproterone acetate (CPA), sold alone under the brand name Androcur or
with ethinylestradiol under the brand names Diane or Diane-35 among others, is an
antiandrogen and
progestin medication used in the treatment of
androgen-dependent conditions such as
acne,
excessive body hair growth,
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
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal a ...
. CPA is taken
by mouth
Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...
one to three times per day.
Common
side effects of high-dose CPA in men include
gynecomastia (breast development) and
feminization. In both men and women, possible side effects of CPA include
low sex hormone levels, reversible
infertility,
sexual dysfunction,
fatigue,
depression,
weight gain, and
elevated liver enzymes. At very high doses in older individuals, significant
cardiovascular complications can occur. Rare but serious adverse reactions of CPA include
blood clots,
liver damage and
brain tumor
A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secon ...
s. CPA can also cause
adrenal insufficiency as a
withdrawal
Withdrawal means "an act of taking out" and may refer to:
* Anchoresis (withdrawal from the world for religious or ethical reasons)
* '' Coitus interruptus'' (the withdrawal method)
* Drug withdrawal
* Social withdrawal
* Taking of money from ...
effect if it is discontinued abruptly from a high dosage. CPA blocks the effects of
androgens such as
testosterone in the body, which it does by preventing them from interacting with their
biological target, the
androgen receptor (AR), and by reducing their
production by the
gonads, hence their concentrations in the body.
In addition, it has
progesterone-like effects by activating the
progesterone receptor (PR).
It can also produce weak
cortisol-like effects at very high doses.
CPA was discovered in 1961.
It was originally developed as a progestin.
In 1965, the antiandrogenic effects of CPA were discovered.
CPA was first marketed, as an antiandrogen, in 1973, and was the first antiandrogen to be introduced for medical use.
A few years later, in 1978, CPA was introduced as a progestin in a birth control pill.
It has been described as a "first-generation" progestin
and as the prototypical antiandrogen.
CPA is available widely throughout the world.
An exception is the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...
, where it is not approved for use.
Medical uses
CPA is used as a
progestin and
antiandrogen in
hormonal birth control and in the treatment of
androgen-dependent conditions.
Specifically, CPA is used in
combined birth control pills, in the treatment of androgen-dependent
skin and hair conditions such as
acne,
seborrhea,
excessive hair growth, and
scalp hair loss
Pattern hair loss (also known as androgenetic alopecia (AGA)) is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front ha ...
,
high androgen levels, in
transgender hormone therapy, to treat
prostate cancer, to reduce
sex drive in
sex offenders or men with
paraphilias or
hypersexuality, to treat
early puberty, and for other uses.
It is used both at low doses and at higher doses.
In the United States, where CPA is not available, other medications with antiandrogenic effects are used to treat androgen-dependent conditions instead.
Examples of such medications include
gonadotropin-releasing hormone modulators (GnRH modulators) like
leuprorelin and
degarelix,
nonsteroidal antiandrogens like
flutamide and
bicalutamide, the
diuretic and
steroidal antiandrogen
A steroidal antiandrogen (SAA) is an antiandrogen with a steroidal chemical structure. They are typically antagonists of the androgen receptor (AR) and act both by blocking the effects of androgens like testosterone and dihydrotestosterone (DHT) ...
spironolactone, the
progestin medroxyprogesterone acetate, and the
5α-reductase inhibitors
finasteride and
dutasteride.
The steroidal antiandrogen and progestin
chlormadinone acetate is used as an alternative to CPA in
Japan,
South Korea
South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
, and a few other countries.
Birth control
CPA is used with
ethinylestradiol
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological dis ...
as a
combined birth control pill to prevent
pregnancy. This birth control combination has been available since 1978.
The formulation is taken once daily for 21 days, followed by a 7-day free interval.
[https://www.bayer.ca/omr/online/diane-35-pm-en.pdf ] CPA has also been available in combination with
estradiol valerate (brand name Femilar) as a combined birth control pill in
Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bo ...
since 1993.
High-dose CPA tablets have a contraceptive effect and can be used as a form of birth control, although they are not specifically licensed as such.
Skin and hair conditions
Females
CPA is used as an antiandrogen to treat
androgen-dependent skin and hair conditions such as
acne,
seborrhea,
hirsutism (excessive hair growth),
scalp hair loss
Pattern hair loss (also known as androgenetic alopecia (AGA)) is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front ha ...
, and
hidradenitis suppurativa in women.
These conditions are worsened by the presence of androgens, and by suppressing androgen levels and blocking their actions, CPA improves the symptoms of these conditions. CPA is used to treat such conditions both at low doses as a birth control pill and on its own at higher doses.
A birth control pill containing low-dose CPA in combination with
ethinylestradiol
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological dis ...
to treat acne has been found to result in overall improvement in 75 to 90% of women, with responses approaching 100% improvement.
High-dose CPA alone likewise has been found to improve symptoms of acne by 75 to 90% in women.
Discontinuation of CPA has been found to result in marked recurrence of symptoms in up to 70% of women.
CPA is one of the most commonly used medications in the treatment of hirsutism, hyperandrogenism, and polycystic ovary syndrome in women throughout the world.
Higher dosages of CPA are used in combination with an estrogen specifically at doses of 25 to 100 mg/day cyclically in the treatment of hirsutism in women.
The efficacy of such dosages of CPA in the treatment of hirsutism in women appear to be similar to that of
spironolactone,
flutamide, and
finasteride.
Randomized controlled trials have found that higher dosages of CPA (e.g., 20 mg/day or 100 mg/day) added cyclically to a
birth control pill containing
ethinylestradiol
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological dis ...
and 2 mg/day CPA were no more effective or only marginally more effective in the treatment of severe hirsutism in women than the birth control pill alone.
Maintenance therapy with lower doses of CPA, such as 25 mg/day, has been found to be effective in preventing relapse of symptoms of hirsutism.
CPA has typically been combined with ethinylestradiol, but it can alternatively be used in combination with
hormone replacement therapy dosages of
estradiol instead.
CPA at a dosage of 50 mg/day in combination with 100 μg/day transdermal estradiol patches has been found to be effective in the treatment of hirsutism similarly to the combination of CPA with ethinylestradiol.
The efficacy of the combination of an estrogen and CPA in the treatment of hirsutism in women appears to be due to marked suppression of total and free
androgen levels as well as additional blockade of the
androgen receptor.
Males
CPA has been found to be effective in the treatment of acne in males, with marked improvement in symptoms observed at dosages of 25, 50, and 100 mg/day in different studies.
It can also halt further progression of scalp hair loss in men.
Increased head hair and decreased body hair has been observed with CPA in men with scalp hair loss.
However, its side effects in men, such as
demasculinization,
gynecomastia,
sexual dysfunction,
bone density
Bone density, or bone mineral density, is the amount of bone mineral in bone tissue. The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although clinically it is measured by proxy according to op ...
loss, and reversible
infertility, make the use of CPA in males impractical in most cases.
In addition, lower dosages of CPA, such as 25 mg/day, have been found to be better-tolerated in men.
But such doses also show lower effectiveness in the treatment of acne in men.
High androgen levels
CPA is used as an antiandrogen to treat
high androgen levels and associated
symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...
s such as
masculinization due to conditions like
polycystic ovary syndrome (PCOS) and
congenital adrenal hyperplasia (CAH) in women.
It is almost always combined with an estrogen, such as
ethinylestradiol
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological dis ...
, when it is used in the treatment of PCOS in women.
Menopausal hormone therapy
CPA is used at low doses in
menopausal hormone therapy in combination with an estrogen to provide
endometrial protection and treat
menopausal symptoms.
It is used in menopausal hormone therapy under the brand name Climen, which is a sequential preparation that contains 2 mg
estradiol valerate and 1 mg CPA.
Climen was the first product for use in menopausal hormone therapy containing CPA to be marketed.
It is available in more than 40 countries.
Transgender hormone therapy
CPA is widely used as an
antiandrogen and
progestogen in
feminizing hormone therapy for
transgender women.
It is used orally at a dosage of 10 to 100 mg/day and by intramuscular injection at a dosage of 300 mg once every 4 weeks.
Studies have found that 10, 25, and 50 mg/day CPA in combination with estrogen all result in equivalent and full testosterone suppression in transgender women.
In light of risks of CPA such as fatigue, blood clots, benign brain tumors, and liver damage, the use of lower dosages of the medication may help to minimize such risks.
The side effects of CPA are more acceptable for transgender women than for cisgender men.
CPA has also been used as a
puberty blocker and hence as an antiandrogen and
antiestrogen to suppress
puberty in
transgender youth, although
GnRH modulators are primarily used for this purpose.
Prostate cancer
CPA is used as an antiandrogen monotherapy and means of
androgen deprivation therapy in the
palliative treatment of
prostate cancer in men.
It is used at very high doses by mouth or by intramuscular injection to treat this disease. Antiandrogens do not cure prostate cancer, but can significantly extend life in men with the disease.
CPA has similar effectiveness to
GnRH modulators and
surgical castration,
high-dose estrogen
High-dose estrogen (HDE) is a type of hormone therapy in which high doses of estrogens are given. When given in combination with a high dose of a progestogen, it has been referred to as pseudopregnancy. It is called this because the estrogen and p ...
therapy (e.g., with
diethylstilbestrol), and high-dose
nonsteroidal antiandrogen monotherapy (e.g., with
bicalutamide), but has significantly inferior effectiveness to
combined androgen blockade with a GnRH modulator and a nonsteroidal antiandrogen (e.g., with bicalutamide or
enzalutamide).
In addition, the combination of CPA with a GnRH modulator or surgical castration has not been found to improve outcomes relative to a GnRH modulator or surgical castration alone, in contrast to nonsteroidal antiandrogens.
Due to its inferior effectiveness,
tolerability, and
safety, CPA is rarely used in the treatment of prostate cancer today, having largely been superseded by GnRH modulators and nonsteroidal antiandrogens.
CPA is the only steroidal antiandrogen that continues to be used in the treatment of prostate cancer.
Dose-ranging studies of CPA for prostate cancer were not performed, and the optimal dosage of CPA for the treatment of the condition has not been established.
A dosage range of oral CPA of 100 to 300 mg/day is used in the treatment of prostate cancer, but generally 150 to 200 mg/day oral CPA is used.
Schröder (1993, 2009) reviewed the issue of CPA dosage and recommended a dosage of 200 to 300 mg/day for CPA as a monotherapy and a dosage of 100 to 200 mg/day for CPA in
combined androgen blockade (that is, CPA in combination with
surgical or
medical castration
Chemical castration is castration via anaphrodisiac drugs, whether to reduce libido and sexual activity, to treat cancer, or otherwise. Unlike surgical castration, where the gonads are removed through an incision in the body,[ ...]
).
However, the combination of CPA with castration for prostate cancer has been found to significantly decrease
overall survival compared to castration alone.
Hence, the use CPA as the antiandrogen component in combined androgen blockade would appear not to be advisable.
When used by intramuscular injection to treat prostate cancer, CPA is used at a dosage of 300 mg once a week.
The combination of CPA with an estrogen such as
ethinylestradiol sulfonate or low-dose
diethylstilbestrol has been used as a form of combined androgen blockade and as an alternative to the combination of CPA with surgical or medical castration.
Sexual deviance
CPA is used as an antiandrogen and form of
chemical castration in the treatment of
paraphilias and
hypersexuality in men.
It is used to treat
sex offenders. The medication is approved in more than 20 countries for this indication and is predominantly employed in
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...
,
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...
, and the
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
.
CPA works by decreasing
sex drive and
sexual arousal
Sexual arousal (also known as sexual excitement) describes the Physiology, physiological and psychological responses in preparation for sexual intercourse or when exposed to Sexual stimulation, sexual stimuli. A number of physiological respons ...
and producing
sexual dysfunction. CPA can also be used to reduce sex drive in individuals with inappropriate sexual behaviors, such as people with
intellectual disability and
dementia.
The medication is also useful for treating self-harmful sexual behavior, such as
masochism.
CPA has comparable effectiveness to
medroxyprogesterone acetate in suppressing sexual urges and function but appears to be less effective than
GnRH modulators like
leuprorelin and has more
side effects.
High-dose CPA significantly decreases
sexual fantasies and
sexual activity in 80 to 90% of men with paraphilias.
In addition, it has been found to decrease the rate of reoffending in sex offenders from 85% to 6%, with most of the reoffenses being committed by individuals who did not follow their CPA treatment prescription.
It has been reported that in 80% of cases, 100 mg/day CPA is adequate to achieve the desired reduction of sexuality, whereas in the remaining 20% of cases, 200 mg/day is sufficient.
When only a partial reduction in sexuality is desired, 50 mg/day CPA can be useful.
Reduced sexual desire and erectile function occurs with CPA by the end of the first week of treatment, and becomes maximal within three to four weeks.
The dosage range is 50 to 300 mg/day.
Early puberty
CPA is used as an antiandrogen and antiestrogen to treat
precocious puberty in boys and girls.
However, it is not fully satisfactory for this indication because it is not able to completely suppress puberty.
For this reason, CPA has mostly been superseded by
GnRH agonists in the treatment of precocious puberty.
CPA is not satisfactory for
gonadotropin-independent precocious puberty
Familial male-limited precocious puberty, often abbreviated as FMPP, also known as familial sexual precocity or gonadotropin-independent testotoxicosis, is a form of gonadotropin-independent precocious puberty in which boys experience early onset ...
.
CPA has been used at dosages of 50 to 300 mg/m
2 to treat precocious puberty.
Other uses
CPA is useful in the treatment of
hot flashes, for instance due to
androgen deprivation therapy for prostate cancer.
CPA is useful for suppressing the testosterone flare at the initiation of GnRH agonist therapy.
It has been used successfully both alone and in combination with
estrogen
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal a ...
s such as
diethylstilbestrol for this purpose.
Available forms
CPA is available in the form of
oral tablet
Tablet may refer to:
Medicine
* Tablet (pharmacy), a mixture of pharmacological substances pressed into a small cake or bar, colloquially called a "pill"
Computing
* Tablet computer, a mobile computer that is primarily operated by touching the s ...
s alone (higher-dose; 10 mg, 50 mg, 100 mg) or in combination with
ethinylestradiol
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological dis ...
or
estradiol valerate (low-dose; 1 or 2 mg CPA) and in the form of
ampoules for
intramuscular injection (higher-dose; 100 mg/mL, 300 mg/3 mL; brand name Androcur Depot).
The higher-dose formulations are used to treat prostate cancer and certain other androgen-related indications while the low-dose formulations which also have an estrogen are used as
combined
Combined may refer to:
* Alpine combined (skiing), the combination of slalom and downhill skiing as a single event
** Super combined (skiing)
* Nordic combined (skiing), the combination of cross country skiing and ski jumping as a single event
* T ...
birth control pills and are used in
menopausal hormone therapy for the treatment of
menopausal symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...
s.
Contraindications
Contraindications of CPA include:
*
Hypersensitivity to CPA or any of the other components of the medication
*
Pregnancy,
lactation, and
breastfeeding
*
Puberty (except if being used to treat precocious puberty or delay puberty)
*
Liver diseases and
liver dysfunction
*
Chronic kidney disease
*
Dubin–Johnson syndrome and
Rotor syndrome
Rotor syndrome (also known as Rotor type hyperbilirubinemia) is a rare cause of mixed direct (conjugated) and indirect (unconjugated) hyperbilirubinemia, relatively benign, autosomal recessive bilirubin disorder characterized by non-hemolytic j ...
*
History of jaundice or persistent pruritus during pregnancy
* History of
herpes during pregnancy
* Previous or existing
liver tumors (only if not due to
metastases from prostate cancer)
* Previous or existing
meningioma,
hyperprolactinemia, or
prolactinoma
*
Wasting syndromes (except in inoperable prostate cancer)
* Severe
depression
* Previous or existing
thromboembolic processes, as well as
stroke
Stroke (also known as a cerebrovascular accident (CVA) or brain attack) is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic ...
and
myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ...
* Severe
diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
with
vascular changes
*
Sickle-cell anemia
When CPA is used in combination with an estrogen, contraindications for
birth control pills should also be considered.
Side effects
CPA is generally well-
tolerated and has a mild
side-effect
In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...
profile regardless of dosage when it is used in combination with an estrogen in women.
Side effects of CPA in general include
hypogonadism (low sex-hormone levels) and associated
symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...
s such as
demasculinization,
sexual dysfunction,
infertility, and
osteoporosis (fragile bones);
breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues.
In females, it serves as the mammary gland, which produces and s ...
changes such as
breast tenderness,
breast enlargement, and
gynecomastia (breasts in men);
emotional changes such as
fatigue and
depression; and other side effects such as
vitamin B12 deficiency, weak
glucocorticoid effects, and
elevated liver enzymes.
Weight gain can occur with CPA when it is used at high doses.
Some of the side effects of CPA can be improved or fully prevented if it is combined with an estrogen to prevent
estrogen deficiency.
Few
quantitative data are available on many of the potential side effects of CPA.
Pooled tolerability data for CPA is not available in the literature.
Cyproterone is also known to suppress andrenocortical function.
At very high doses in aged men with prostate cancer, CPA can cause
cardiovascular side effects. Rarely, CPA can produce
blood clots,
liver toxicity
Hepatotoxicity (from ''hepatic toxicity'') implies chemical-driven liver damage. Drug-induced liver injury is a cause of acute and chronic liver disease caused specifically by medications and the most common reason for a drug to be withdrawn fro ...
(including
hepatitis,
liver failure, and
liver cancer),
excessively high prolactin levels, and certain
benign brain tumor
A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secon ...
s including
meningiomas (tumors of the
meninge
In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in ...
s) and
prolactinomas (
prolactin-secreting tumors of the
pituitary gland). Upon
discontinuation from high doses, CPA can produce
adrenal insufficiency as a
withdrawal
Withdrawal means "an act of taking out" and may refer to:
* Anchoresis (withdrawal from the world for religious or ethical reasons)
* '' Coitus interruptus'' (the withdrawal method)
* Drug withdrawal
* Social withdrawal
* Taking of money from ...
effect.
Overdose
CPA is relatively safe in acute
overdose.
It is used at very high doses of up to 300 mg/day by mouth and 700 mg per week by intramuscular injection.
For comparison, the dose of CPA used in birth control pills is 2 mg/day.
There have been no deaths associated with CPA overdose.
There are no specific
antidotes for CPA overdose, and treatment should be
symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...
-based.
Gastric lavage can be used in the event of oral overdose within the last 2 to 3 hours.
Interactions
Inhibitor
Inhibitor or inhibition may refer to:
In biology
* Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity
* Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ...
s and
inducers of the
cytochrome P450
Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compo ...
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
CYP3A4 may
interact with CPA.
Examples of strong CYP3A4 inhibitors include
ketoconazole,
itraconazole,
clotrimazole, and
ritonavir, while examples of strong CYP3A4 inducers include
rifampicin,
rifampin,
phenytoin,
carbamazepine,
phenobarbital, and
St. John's wort.
Certain
anticonvulsant medications can substantially reduce levels of CPA, by as much as 8-fold.
Pharmacology
Pharmacodynamics
CPA has
antiandrogenic activity,
progestogenic activity,
weak
partial glucocorticoid activity,
weak
steroidogenesis inhibitor activity,
and
agonist activity at the
pregnane X receptor.
It has no
estrogen
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal a ...
ic or
antimineralocorticoid activity.
In terms of
potency, CPA is described as a highly potent progestogen, a moderately potent antiandrogen, and a weak glucocorticoid.
Due to its progestogenic activity, CPA has
antigonadotropic
An antigonadotropin is a drug which suppresses the activity and/or downstream effects of one or both of the gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). This results in an inhibition of the hypothalamic-pituita ...
effects, and is able to suppress
fertility
Fertility is the capability to produce offspring through reproduction following the onset of sexual maturity. The fertility rate is the average number of children born by a female during her lifetime and is quantified demographically. Ferti ...
and
sex-hormone levels in both males and females.
Pharmacokinetics
CPA can be taken
by mouth
Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...
or by
injection into muscle
Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have l ...
.
It has near-complete oral
bioavailability, is highly and exclusively bound to
albumin in terms of
plasma protein binding, is
metabolized in the
liver
The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...
by
hydroxylation and
conjugation
Conjugation or conjugate may refer to:
Linguistics
*Grammatical conjugation, the modification of a verb from its basic form
* Emotive conjugation or Russell's conjugation, the use of loaded language
Mathematics
*Complex conjugation, the change ...
, has
15β-hydroxycyproterone acetate
15β-Hydroxycyproterone acetate (15β-OH-CPA) is a steroidal antiandrogen and the major metabolite of cyproterone acetate (CPA). It is formed from CPA in the liver by hydroxylation via the cytochrome P450 enzyme CYP3A4. During therapy with CPA ...
(15β-OH-CPA) as a single major
active metabolite, has a long
elimination half-life of about 2 to 4 days regardless of route of administration, and is
excreted in
feces primarily and to a lesser extent in
urine.
Chemistry
CPA, also known as 1α,2α-methylene-6-chloro-17α-acetoxy-δ
6-progesterone or as 1α,2α-methylene-6-chloro-17α-hydroxypregna-4,6-diene-3,20-dione acetate, is a
synthetic Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to:
Science
* Synthetic chemical or compound, produced by the process of chemical synthesis
* Synthetic o ...
pregnane steroid
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...
and an
acetylated derivative
In mathematics, the derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of calculus. ...
of
17α-hydroxyprogesterone.
It is structurally related to other 17α-hydroxyprogesterone derivatives such as
chlormadinone acetate,
hydroxyprogesterone caproate,
medroxyprogesterone acetate, and
megestrol acetate.
Synthesis
Chemical syntheses of CPA have been published.
The following is one such synthesis:

The dehydrogenation of
17α-hydroxyprogesterone acetate
Hydroxyprogesterone acetate (OHPA), sold under the brand name Prodox, is an oral administration, orally active progestin related to hydroxyprogesterone caproate (OHPC) which has been used in clinical medicine, clinical and veterinary medicine. I ...
02-23-8
The hyphen-minus is the most commonly used type of hyphen, widely used in digital documents. It is the only character that looks like a minus sign or a dash in many character sets such as ASCII or on most keyboards, so it is also used as such. ...
(1) with
chloranil (tetrachloro-p-benzoquinone) gives a compound that has been called melengestro acetate
25-51-4(2). Dehydrogenation with selenium dioxide gives 17-acetoxy-1,4,6-pregnatriene-3,20-dione
668-75-9(3). Reacting this with diazomethane results in a 1,3-dipolar addition reaction at C1–C2 of the double bond of the steroid system, which forms a derivative of dihydropyrazole
CID:134990386(4). This compound cleaves when reacted with
perchloric acid,
[Rudolf Wiechert, (1964).] releasing nitrogen molecules and forming a cyclopropane derivative, 6-deschloro cyproterone acetate
701-50-0
7 (seven) is the natural number following 6 and preceding 8. It is the only prime number preceding a cube.
As an early prime number in the series of positive integers, the number seven has greatly symbolic associations in religion, mythology, s ...
(5). Selective oxidation of the C6=C7 olefin with benzoyl peroxide gives the epoxide, i.e. 6-deschloro-6,7-epoxy cyproterone
5423-97-9
54 may refer to:
* 54 (number)
* one of the years 54 BC, AD 54, 1954, 2054
* ''54'' (novel), a 2002 novel by Wu Ming
* Studio 54, a New York City nightclub from 1977 until 1981
* ''54'' (film), a 1998 American drama film about the club
* ''54'' ...
(6). The penultimate step involves a reaction with hydrochloric acid in acetic acid, resulting in the formation of chlorine and its subsequent dehydration, and a simultaneous opening of the cyclopropane ring giving 1α-(chloromethyl) chlormadinone acetate
7183-98-1(7). The heating of this in collidine reforms the cyclopropane ring, completing the synthesis of CPA (8).
History
CPA was first
synthesized in 1961 by
Rudolf Wiechert, a
Schering employee, and together with
Friedmund Neumann in
Berlin
Berlin is Capital of Germany, the capital and largest city of Germany, both by area and List of cities in Germany by population, by population. Its more than 3.85 million inhabitants make it the European Union's List of cities in the European U ...
, they filed for a patent for CPA as "progestational agent" in 1962.
The antiandrogenic activity of CPA was discovered serendipitously by Hamada, Neumann, and Karl Junkmann in 1963.
Along with the steroidal antiandrogens
benorterone
Benorterone, also known by its developmental code name SKF-7690 and as 17α-methyl-''B''-nortestosterone, is a steroidal antiandrogen which was studied for potential medical use but was never marketed. It was the first known antiandrogen to be ...
(17α-methyl-''B''-nortestosterone; SKF-7690),
cyproterone,
BOMT
BOMT, also known by its developmental code name Ro 7-2340 and as 6α-bromo-4-oxa-17α-methyl-5α-dihydrotestosterone, is a synthetic steroidal antiandrogen which was first developed in 1970 and was never marketed for medical use. It is the 6α- b ...
(Ro 7–2340), and
trimethyltrienolone (R-2956) and the
nonsteroidal antiandrogens
flutamide and
DIMP (Ro 7–8117), CPA was one of the first antiandrogens to be discovered and researched.
CPA was initially developed as a progestogen for the prevention of
threatened abortion
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemical ...
.
As part of its development, it was assessed for androgenic activity to ensure that it would not produce
teratogenic effects in female
fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal develo ...
es.
The drug was administered to
pregnant rats and its effects on the rat fetuses were studied.
To the surprise of the researchers, all of the rat pups born appeared to be female.
After 20 female rat pups in a row had been counted, it was clear that this could not be a chance occurrence.
The rat pups were further evaluated and it was found that, in terms of
karyotype, about 50% were actually males.
The male rat pups had been feminized, and this resultant finding constituted the discovery of the powerful antiandrogenic activity of CPA.
A year after patent approval in 1965, Neumann published additional evidence of CPA's antiandrogenic effect in rats; he reported an "organizational effect of CPA on the brain".
CPA started being used in animal experiments around the world to investigate how antiandrogens affected fetal
sexual differentiation.
The first clinical use of CPA in the treatment of
sexual deviance
Paraphilia (previously known as sexual perversion and sexual deviation) is the experience of intense sexual arousal to atypical objects, situations, fantasies, behaviors, or individuals. It has also been defined as sexual interest in anything ot ...
and
prostate cancer occurred in 1966.
It was first studied in the treatment of androgen-dependent skin and hair symptoms, specifically acne, hirsutism, seborrhea, and scalp hair loss, in 1969.
CPA was first approved for medical use in 1973 in
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...
under the brand name Androcur.
In 1977, a formulation of CPA was introduced for use by intramuscular injection.
CPA was first marketed as a birth control pill in 1978 in combination with ethinylestradiol under the brand name Diane.
Following
phase III clinical trials, CPA was approved for the treatment of prostate cancer in Germany in 1980.
CPA became available in
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...
as Androcur in 1987, as Androcur Depot in 1990, and as Diane-35 in 1998.
Conversely, CPA was never introduced in any form in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...
.
This was reportedly due to concerns about
breast tumors observed with high-dose
pregnane progestogens in beagle dogs as well as concerns about potential
teratogenicity in pregnant women.
Use of CPA in
transgender women, an
off-label indication, was reported as early as 1977.
The use of CPA in transgender women was well-established by the early 1990s.
The history of CPA, including its discovery, development, and marketing, has been reviewed.
Society and culture
Generic names
The
English and
generic name of CPA is ''cyproterone acetate'' and this is its , , and .
The English and generic name of unacetylated
cyproterone is ''cyproterone'' and this is its and ,
while ''cyprotérone'' is the and
French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
name and ''ciproterone'' is the and
Italian name.
The name of unesterified cyproterone in
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...
is ''cyproteronum'', in
German is ''cyproteron'', and in
Spanish is ''ciproterona''.
These names of cyproterone correspond for CPA to ''acétate de cyprotérone'' in French, ''acetato de ciproterona'' in Spanish, ''ciproterone acetato'' in Italian, ''cyproteronacetat'' in German, ''cyproteronacetaat'' in
Dutch, and ''ciproteron acetat'' in Slavic. CPA is also known by the developmental code names ''SH-80714'' and ''SH-714'', while unacetylated cyproterone is known by the developmental code names ''SH-80881'' and ''SH-881''.
Brand names
CPA is marketed under brand names including Androcur, Androcur Depot, Androcur-100, Androstat, Asoteron, Cyprone, Cyproplex, Cyprostat, Cysaxal, Imvel, and Siterone.
When CPA is formulated in combination with ethinylestradiol, it is also known as ''co-cyprindiol'', and brand names for this formulation include Andro-Diane, Bella HEXAL 35, Chloe, Cypretil, Cypretyl, Cyproderm, Diane, Diane Mite, Diane-35, Dianette, Dixi 35, Drina, Elleacnelle, Estelle, Estelle-35, Ginette, Linface, Minerva, Vreya, and Zyrona.
CPA is also marketed in combination with
estradiol valerate as Climen, Climene, Elamax, and Femilar.
Availability

CPA is widely available throughout the world, and is marketed in almost every developed country,
with the notable major exceptions of the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...
and
Japan.
[http://www.micromedexsolutions.com/micromedex2/] In almost all countries in which CPA is marketed, it is available both alone and in combination with an estrogen in birth control pills.
CPA is marketed widely in combination with both
ethinylestradiol
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological dis ...
and
estradiol valerate.
CPA-containing birth control pills are available in
South Korea
South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
, but CPA as a standalone medication is not marketed in this country.
In Japan and South Korea, the closely related antiandrogen and progestin
chlormadinone acetate, as well as other medications, are used instead of CPA.
Specific places in which CPA is marketed include the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
, elsewhere throughout
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...
,
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...
,
Australia,
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...
,
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...
,
Latin America
Latin America or
* french: Amérique Latine, link=no
* ht, Amerik Latin, link=no
* pt, América Latina, link=no, name=a, sometimes referred to as LatAm is a large cultural region in the Americas where Romance languages — languages derived ...
, and
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...
.
CPA is not marketed in most of
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
and the
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
.
It has been said that the lack of availability of CPA in the United States explains why there are relatively few studies of it in the treatment of androgen-dependent conditions such as hyperandrogenism and hirsutism in women.
Generation
Progestins in birth control pills are sometimes grouped by generation.
While the
19-nortestosterone progestins are consistently grouped into generations, the
pregnane progestins that are or have been used in birth control pills are typically omitted from such classifications or are grouped simply as "miscellaneous" or "pregnanes".
In any case, CPA has been described as a "first-generation" progestin similarly to closely related progestins like
chlormadinone acetate,
medroxyprogesterone acetate, and
megestrol acetate.
Research
CPA has been studied and used in combination with low-dose
diethylstilbestrol in the treatment of
prostate cancer.
The combination results in suppression of testosterone levels into the
castrate
Castration is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses pharmaceut ...
range, which normally cannot be achieved with CPA alone.
CPA has been studied as a form of
androgen deprivation therapy for the treatment of
benign prostatic hyperplasia
Benign prostatic hyperplasia (BPH), also called prostate enlargement, is a noncancerous increase in size of the prostate gland. Symptoms may include frequent urination, trouble starting to urinate, weak stream, inability to urinate, or loss ...
(enlarged prostate).
The medication has been studied in the treatment of
breast cancer
Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or ...
as well.
CPA has been studied for use as a potential
male hormonal contraceptive both alone and in combination with
testosterone in men.
CPA was under development by Barr Pharmaceuticals in the 2000s for the treatment of
hot flashes in prostate cancer patients in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...
.
It reached
phase III clinical trials for this indication and had the tentative brand name CyPat but development was ultimately discontinued in 2008.
CPA is not satisfactorily effective as
topical
A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of class ...
antiandrogen, for instance in the treatment of
acne.
CPA has been used to treat
estrogen hypersensitivity vulvovaginitis in women.
CPA has been investigated for use in reducing
aggression and
self-injurious behavior via its antiandrogenic effects in conditions like
autism spectrum disorders,
dementias like
Alzheimer's disease, and
psychosis.
CPA may be effective in the treatment of
obsessive–compulsive disorder (OCD).
CPA has been studied in the treatment of
cluster headaches in men.
See also
*
Estradiol valerate/cyproterone acetate
Estradiol valerate/cyproterone acetate (EV/CPA), sold under the brand names Climen and Femilar among others, is a combination product of estradiol valerate (EV), an estrogen, and cyproterone acetate (CPA), a progestogen, which is used in menopau ...
*
Ethinylestradiol/cyproterone acetate
References
Further reading
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External links
Die Geschichte des Wirkstoffs Cyproteronazetat: Von der "Pille für den Mann" zum "Hautpflegemittel mit Empfängnisschutz" [The History of Cyproterone Acetate: From the "Pill for Men" to the "Skin Care Product and Contraceptive"/nowiki> - Arznei-Telegramm]
Google Translate">[Google Translate/nowiki>">/nowiki>Google Translate
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/nowiki>
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{{Androgen receptor modulators
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{{Xenobiotic-sensing receptor modulators
Cyproterone acetate,
3β-Hydroxysteroid dehydrogenase inhibitors
Acetate esters
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Antigonadotropins
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