RU-486
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Mifepristone, and also known by its developmental code name RU-486, is a drug typically used in combination with
misoprostol Misoprostol is a synthetic prostaglandin medication used to prevent and treat stomach and duodenal ulcers, induce labor, cause an abortion, and treat postpartum bleeding due to poor contraction of the uterus. It is taken by mouth when used ...
to bring about a
medical abortion A medical abortion, also known as medication abortion or non-surgical abortion, occurs when drugs (medication) are used to bring about an abortion. Medical abortions are an alternative to surgical (also called procedural or instrumentation) a ...
during pregnancy. This combination is 97% effective during the first 63 days (9 weeks) of
pregnancy Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs ...
, yet effective in the second trimester as well. It is also used on its own to treat
Cushing's syndrome Cushing's syndrome is a collection of signs and symptoms due to prolonged exposure to glucocorticoids such as cortisol. Signs and symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, ...
or for use as a low-dose
emergency contraceptive Emergency contraception (EC) is a birth control measure, used after sexual intercourse to prevent pregnancy. There are different forms of EC. Emergency contraceptive pills (ECPs), sometimes simply referred to as emergency contraceptives (ECs), ...
. The most common adverse effects include abdominal pain, feeling tired, and vaginal bleeding. Serious side effects may include heavy vaginal bleeding, bacterial infection, and, if pregnant, birth defects. When used, appropriate follow-up care needs to be available. Mifepristone is primarily an antiprogestogen. It works by blocking the effects of
progesterone Progesterone (; P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the ma ...
, making both the
cervix The cervix (: cervices) or cervix uteri is a dynamic fibromuscular sexual organ of the female reproductive system that connects the vagina with the uterine cavity. The human female cervix has been documented anatomically since at least the time ...
and uterine vessels dilate and causing uterine contraction. Mifepristone also works, to a less extent, as an antiglucocorticoid and diminishes the effects of hypercortisolism. Mifepristone was developed in 1980 and came into use in France in 1987. It became available in the United States in 2000, for medication abortion, and in 2010, for Cushing's syndrome. It is on the
World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health s ...
. Mifepristone was approved in Canada in January 2017.


Medical uses


Abortion

Mifepristone followed by a
prostaglandin Prostaglandins (PG) are a group of physiology, physiologically active lipid compounds called eicosanoids that have diverse hormone-like effects in animals. Prostaglandins have been found in almost every Tissue (biology), tissue in humans and ot ...
analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog ...
(
misoprostol Misoprostol is a synthetic prostaglandin medication used to prevent and treat stomach and duodenal ulcers, induce labor, cause an abortion, and treat postpartum bleeding due to poor contraction of the uterus. It is taken by mouth when used ...
or
gemeprost Gemeprost (16, 16-dimethyl-trans-delta2 PGE1 methyl ester) is an analogue of prostaglandin E1. Clinical use It is used as a treatment for obstetric bleeding. It is used with mifepristone to terminate pregnancy up to 24 weeks gestation. Sid ...
) is used for
medical abortion A medical abortion, also known as medication abortion or non-surgical abortion, occurs when drugs (medication) are used to bring about an abortion. Medical abortions are an alternative to surgical (also called procedural or instrumentation) a ...
. Medical organizations have found this combination to be safe and effective. Guidelines from the
Royal College of Obstetricians and Gynaecologists The Royal College of Obstetricians and Gynaecologists (RCOG) is a professional association based in London, United Kingdom. Its members, including people with and without medical degrees, work in the field of obstetrics and gynaecology, that is ...
describe medication abortion using mifepristone and
misoprostol Misoprostol is a synthetic prostaglandin medication used to prevent and treat stomach and duodenal ulcers, induce labor, cause an abortion, and treat postpartum bleeding due to poor contraction of the uterus. It is taken by mouth when used ...
as effective and appropriate at any
gestational age In obstetrics, gestational age is a measure of the age of a pregnancy taken from the beginning of the woman's last menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method, if available. Such metho ...
. The
World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...
and the
American College of Obstetricians and Gynecologists The American College of Obstetricians and Gynecologists (ACOG) is a professional association of physicians specializing in obstetrics and gynecology in the United States. Several Latin American countries are also represented within Districts of ...
recommend mifepristone followed by misoprostol for first- and second- trimester medical abortion. Mifepristone alone is less effective, resulting in abortion within 1–2 weeks in anywhere from 54% to 92% of pregnancies, according to review of 13 studies.


Cushing's syndrome

Mifepristone is used for the medical treatment of
high blood sugar Hyperglycemia is a condition where unusually high amount of glucose is present in blood. It is defined as blood glucose level exceeding 6.9 mmol/L (125 mg/dL) after fasting for 8 hours or 10 mmol/L (180 mg/dL) 2 hours after eating. Blood gluco ...
caused by high
cortisol Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal corte ...
levels in the blood (hypercortisolism) in adults with endogenous
Cushing's syndrome Cushing's syndrome is a collection of signs and symptoms due to prolonged exposure to glucocorticoids such as cortisol. Signs and symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, ...
who also have
type 2 diabetes mellitus Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ur ...
or
glucose intolerance Prediabetes is a component of metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus. It usually does not cause symptoms, but people with prediabetes often have obesity ( ...
and have failed surgery or cannot have surgery. In a Phase III trial, it improved glycemic control, increased
insulin sensitivity Insulin resistance (IR) is a pathological response in which cells in insulin-sensitive tissues in the body fail to respond normally to the hormone insulin or downregulate insulin receptors in response to hyperinsulinemia. Insulin is a hormone ...
, and reduced body weight regardless of the cause of CS.


Medical management of early pregnancy loss

Mifepristone combined with misoprostol is the preferred medication regimen for management of early pregnancy loss. While misoprostol alone can be used, the addition of a dose of mifepristone twenty-four hours before misoprostol administration improves treatment efficacy.


Other uses

Mifepristone at low doses has been used for
emergency contraception Emergency contraception (EC) is a birth control measure, used after sexual intercourse to prevent pregnancy. There are different forms of EC. Emergency contraceptive pills (ECPs), sometimes simply referred to as emergency contraceptives (ECs), ...
. Mifepristone has also been used to treat symptomatic
leiomyoma A leiomyoma, also known as a fibroid, is a benign smooth muscle tumor that very rarely becomes cancer (0.1%). They can occur in any organ, but the most common forms occur in the uterus, small bowel, and the esophagus. Polycythemia may occur due ...
(uterine fibroids) and
endometriosis Endometriosis is a disease in which Tissue (biology), tissue similar to the endometrium, the lining of the uterus, grows in other places in the body, outside the uterus. It occurs in women and a limited number of other female mammals. Endomet ...
. As elevated cortisol levels have been implicated in
psychotic depression Psychotic depression, also known as depressive psychosis, is a major depressive episode that is accompanied by psychotic symptoms.Hales E and Yudofsky JA, eds, The American Psychiatric Press Textbook of Psychiatry, Washington, DC: American Psych ...
, mifepristone has been used as a treatment.


Side effects

Serious complications with mifepristone are rare with about 0.04%–0.09% requiring hospitalization and 0.05% requiring blood transfusion. Nearly all women using the mifepristone/misoprostol regimen experienced abdominal pain, uterine cramping, and vaginal bleeding or spotting for an average of 9–16 days. For most women, the most severe cramps after use of misoprostol last for less than 6 hours and can generally be managed with ibuprofen. Up to 8% of women experienced some type of bleeding for 30 days or more. Other less common side effects included
nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. It can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the throat. Over 30 d ...
,
vomiting Vomiting (also known as emesis, puking and throwing up) is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteritis, pre ...
, diarrhea, dizziness, fatigue, and
fever Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with Human body temperature, body temperature exceeding the normal range caused by an increase in the body's temperature Human body temperature#Fever, s ...
.
Pelvic inflammatory disease Pelvic inflammatory disease (PID), also known as pelvic inflammatory disorder, is an infection of the upper part of the female reproductive system, mainly the uterus, fallopian tubes, and ovaries, and inside of the pelvis. Often, there may be no ...
is a very rare but serious complication. Excessive bleeding and incomplete termination of a pregnancy require further intervention by a doctor (such as a repeat dose of misoprostol or a
vacuum aspiration Vacuum or suction aspiration is a procedure that uses a vacuum source to remove an embryo or fetus through the cervix. The procedure is performed to induce abortion, as a treatment for incomplete spontaneous abortion (otherwise commonly known as ...
). Mifepristone is
contraindicated In medicine, a contraindication is a condition (a situation or factor) that serves as a reason not to take a certain medical treatment due to the harm that it would cause the patient. Contraindication is the opposite of indication, which is a rea ...
in the presence of
adrenal The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which ...
failure, long-term oral
corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are invo ...
therapy (although inhaled and topical steroids are not contraindications),
hemorrhagic Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, va ...
disorders, inherited
porphyria Porphyria ( or ) is a group of disorders in which substances called porphyrins build up in the body, adversely affecting the skin or nervous system. The types that affect the nervous system are also known as Porphyria#Acute porphyrias, acute p ...
, and hemophilia or
anticoagulant An anticoagulant, commonly known as a blood thinner, is a chemical substance that prevents or reduces the coagulation of blood, prolonging the clotting time. Some occur naturally in blood-eating animals, such as leeches and mosquitoes, which ...
use. Women with an
intrauterine device An intrauterine device (IUD), also known as an intrauterine contraceptive device (IUCD or ICD) or coil, is a small, often T-shaped birth control device that is inserted into the uterus to prevent pregnancy. IUDs are a form of long-acting rever ...
in their uterus should remove the IUD prior to medication abortion to avoid unnecessary cramping. Mifepristone is not effective in treating
ectopic pregnancy Ectopic pregnancy is a complication of pregnancy in which the embryo attaches outside the uterus. Signs and symptoms classically include abdominal pain and vaginal bleeding, but fewer than 50 percent of affected women have both of these sympto ...
. A postmarketing summary found, of about 1.52 million women who had received mifepristone until April 2011 in the United States, 14 were reported to have died after application. Eight of these cases were associated with
sepsis Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...
; the other six had various causes such as drug abuse and suspected murder. Other incidents reported to the FDA included 612 nonlethal hospitalizations, 339 blood transfusions, 48 severe infections, and 2,207 (0.15%) adverse events altogether. No long-term studies to evaluate the
carcinogenic A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and Biological agent, biologic agent ...
potential of mifepristone have been performed. This is in accord with ICH guidelines, which do not require carcinogenicity testing in nongenotoxic drugs intended for administration for less than six months.


Pregnancy

Mifepristone alone results in abortion within 1–2 weeks in 54% to 92% of pregnancies. The effectiveness increases to greater than 90% if
misoprostol Misoprostol is a synthetic prostaglandin medication used to prevent and treat stomach and duodenal ulcers, induce labor, cause an abortion, and treat postpartum bleeding due to poor contraction of the uterus. It is taken by mouth when used ...
is given after the mifepristone. There is no evidence that the effects of mifepristone can be reversed, although some
anti-abortion Anti-abortion movements, also self-styled as pro-life movements, are involved in the abortion debate advocating against the practice of abortion and its Abortion by country, legality. Many anti-abortion movements began as countermovements in r ...
groups claim that it can be reversed by giving progesterone. Researchers in the United States initiated a trial of the so-called "reversal" regimen in 2019, but stopped prematurely due to serious safety concerns about using mifepristone without follow-up misoprostol. Giving progesterone has not been shown to halt medication abortion, and not completing the combination regimen of mifepristone and misoprostol may cause serious bleeding. In those who continue pregnancy after use of mifepristone together with misoprostol for termination, birth defects may occur. Exposure to a single large dose of mifepristone in newborn rats was not associated with any reproductive problems, although chronic low-dose exposure of newborn rats to mifepristone was associated with structural and functional reproductive abnormalities. Studies in mice, rats, and rabbits revealed developmental abnormalities for rabbits, but not rats or mice.


Pharmacology


Pharmacodynamics

Mifepristone is a
steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...
al antiprogestogen ( IC50 = 0.025 nM for the PR), as well as an
antiglucocorticoid Antiglucocorticoid drugs are a class of medications that act to reduce the effects of glucocorticoids, primarily cortisol, in the body. They include direct glucocorticoid receptor antagonists such as mifepristone and synthesis inhibitors such as ...
(IC50 = 2.2 nM for the GR) and
antiandrogen Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs that prevent androgens like testosterone and dihydrotestosterone (DHT) from mediating their biological effects in the body. They act by blocking t ...
(IC50 = 10 nM for the AR) to a much lesser extent. It antagonizes
cortisol Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal corte ...
action competitively at the
receptor Receptor may refer to: * Sensory receptor, in physiology, any neurite structure that, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and respond ...
level. In the presence of
progesterone Progesterone (; P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the ma ...
, mifepristone acts as a
competitive Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indi ...
progesterone receptor antagonist (in the absence of progesterone, mifepristone acts as a
partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given Receptor (biochemistry), receptor, but have only partial Intrinsic activity, efficacy at the receptor relative to a full agonist. They may also be considered Ligand (bio ...
). Mifepristone is a 19- nor
steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...
with a bulky '' p''-(dimethylamino)
phenyl In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula , and is often represented by the symbol Ph (archaically φ) or Ø. The phenyl group is closely related to benzene and can be viewed as a benzene ...
substituent In organic chemistry, a substituent is one or a group of atoms that replaces (one or more) atoms, thereby becoming a moiety in the resultant (new) molecule. The suffix ''-yl'' is used when naming organic compounds that contain a single bond r ...
above the plane of the molecule at the 11β-position responsible for inducing or stabilizing an inactive
receptor Receptor may refer to: * Sensory receptor, in physiology, any neurite structure that, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and respond ...
conformation and a
hydrophobic In chemistry, hydrophobicity is the chemical property of a molecule (called a hydrophobe) that is seemingly repelled from a mass of water. In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thu ...
1- propynyl substituent below the plane of the molecule at the 17α-position that increases its
progesterone receptor The progesterone receptor (PR), also known as NR3C3 or nuclear receptor subfamily 3, group C, member 3, is a protein found inside cells. It is activated by the steroid hormone progesterone. In humans, PR is encoded by a single ''PGR'' gene resi ...
binding affinity In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from Latin ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usuall ...
. In addition to being an antiprogestogen, mifepristone is also an antiglucocorticoid and a weak
antiandrogen Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs that prevent androgens like testosterone and dihydrotestosterone (DHT) from mediating their biological effects in the body. They act by blocking t ...
. Mifepristone's relative binding affinity at the progesterone receptor is more than twice that of
progesterone Progesterone (; P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the ma ...
, its relative binding affinity at the
glucocorticoid receptor The glucocorticoid receptor (GR or GCR) also known by its gene name ''NR3C1'' ( nuclear receptor subfamily 3, group C, member 1) is the steroid receptor for glucocorticoids such as cortisol. The GR is expressed in almost every cell in the bod ...
is more than three times that of
dexamethasone Dexamethasone is a fluorinated glucocorticoid medication used to treat rheumatic problems, a number of skin diseases, severe allergies, asthma, chronic obstructive pulmonary disease (COPD), croup, brain swelling, eye pain following eye su ...
and more than ten times that of
cortisol Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal corte ...
. Its relative binding affinity at the
androgen receptor The androgen receptor (AR), also known as NR3C4 (nuclear receptor subfamily 3, group C, member 4), is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone, in th ...
is less than one-third that of
testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...
, and it does not bind to the
estrogen receptor Estrogen receptors (ERs) are proteins found in cell (biology), cells that function as receptor (biochemistry), receptors for the hormone estrogen (17β-estradiol). There are two main classes of ERs. The first includes the intracellular estrogen ...
or the
mineralocorticoid receptor The mineralocorticoid receptor (or MR, MLR, MCR), also known as the aldosterone receptor or nuclear receptor subfamily 3, group C, member 2, (NR3C2) is a protein that in humans is encoded by the ''NR3C2'' gene that is located on chromosome 4q31 ...
. Mifepristone as a regular
contraceptive Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth control only be ...
at 2 mg daily prevents
ovulation Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and ...
(1 mg daily does not). A single preovulatory 10-mg dose of mifepristone delays ovulation by three to four days and is as effective an
emergency contraceptive Emergency contraception (EC) is a birth control measure, used after sexual intercourse to prevent pregnancy. There are different forms of EC. Emergency contraceptive pills (ECPs), sometimes simply referred to as emergency contraceptives (ECs), ...
as a single 1.5-mg dose of the
progestin A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural female sex hormone progesterone in the body. A progestin is a '' synthetic'' progestogen. ...
levonorgestrel Levonorgestrel is a hormonal medication used in a number of birth control methods. It is combined with an estrogen to make combination birth control pills. As an emergency birth control, sold under the brand names Plan B One-Step and Julie, ...
. In women, mifepristone at doses greater or equal to 1 mg/kg antagonizes the
endometrial The endometrium is the inner epithelium, epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The funct ...
and myometrial effects of progesterone. In humans, an antiglucocorticoid effect of mifepristone is manifested at doses greater or equal to 4.5 mg/kg by a compensatory increase in
ACTH Adrenocorticotropic hormone (ACTH; also adrenocorticotropin, corticotropin) is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland. It is also used as a medication and diagnostic agent. ACTH is an important ...
and cortisol. In animals, a weak antiandrogenic effect is seen with prolonged administration of very high doses of 10 to 100 mg/kg. In medication abortion regimens, mifepristone blockade of progesterone receptors directly causes endometrial
decidua The decidua is the modified mucosal lining of the uterus (that is, modified endometrium) that forms every month, in preparation for pregnancy. It is shed off each month when there is no fertilized egg to support. The decidua is under the influe ...
l degeneration, cervical softening and dilatation, release of
endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...
prostaglandin Prostaglandins (PG) are a group of physiology, physiologically active lipid compounds called eicosanoids that have diverse hormone-like effects in animals. Prostaglandins have been found in almost every Tissue (biology), tissue in humans and ot ...
s, and an increase in the sensitivity of the myometrium to the contractile effects of prostaglandins. Mifepristone-induced decidual breakdown indirectly leads to
trophoblast The trophoblast (from Greek language, Greek : to feed; and : germinator) is the outer layer of cells of the blastocyst. Trophoblasts are present four days after Human fertilization, fertilization in humans. They provide nutrients to the embryo an ...
detachment, resulting in decreased
syncytiotrophoblast The syncytiotrophoblast (from the Greek 'syn'- "together"; 'cytio'- "of cells"; 'tropho'- "nutrition"; 'blast'- "bud") is the epithelial covering of the highly vascular embryonic placental villi, which invades the wall of the uterus to establish ...
production of hCG, which in turn causes decreased production of progesterone by the
corpus luteum The corpus luteum (Latin for "yellow body"; : corpora lutea) is a temporary endocrine structure in female ovaries involved in the production of relatively high levels of progesterone, and moderate levels of estradiol, and inhibin A. It is the ...
(
pregnancy Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs ...
is dependent on progesterone production by the corpus luteum through the first nine weeks of
gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...
—until
placenta The placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas, and waste exchange between ...
l progesterone production has increased enough to take the place of corpus luteum progesterone production). When followed sequentially by a prostaglandin, mifepristone 200 mg is (100 mg may be, but 50 mg is not) as effective as 600 mg in producing a medical abortion. 'Contragestion' is a term promoted by Étienne-Émile Baulieu in the context of his advocacy of mifepristone, defining it as inclusive of some hypothesized mechanisms of action of some contraceptives and those of mifepristone to induce abortion.













''adj.'' Capable of preventing gestation, either by preventing implantation or by causing the uterine lining to shed after implantation. —''n.'' A contragestive drug or agent.
Also ''contragestant'', ''abortion pill''. A substance called ''mifepristone'', or ''RU-486'', which was developed by Dr. Etienne Baulieu and the Roussel-Uclaf company. The contragestive blocks progesterone receptors in the endometrium (uterine lining), preventing its buildup by progesterone; hence the uterus cannot sustain a pregnancy. It does not prevent fertilization or implantation, so technically it is an ABORTIFACIENT rather than a contraceptive.
Baulieu's definition of a 'contragestive' included any birth control method that could possibly act after
fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...
and before nine-weeks
gestational age In obstetrics, gestational age is a measure of the age of a pregnancy taken from the beginning of the woman's last menstrual period (LMP), or the corresponding age of the gestation as estimated by a more accurate method, if available. Such metho ...
.


Pharmacokinetics

The
elimination half-life Biological half-life (elimination half-life, pharmacological half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the blood plasma. ...
is complex; according to the label: "After a distribution phase, elimination is at first slow, the concentration decreasing by a half between about 12 and 72 hours, and then more rapid, giving an elimination half-life of 18 hours. With radio receptor assay techniques, the terminal half-life is of up to 90 hours, including all metabolites of mifepristone able to bind to progesterone receptors." Metapristone is the major
metabolite In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...
of mifepristone.


Chemistry

Mifepristone, also known as 11β-(4-(dimethylamino)phenyl)-17α-(1-propynyl)estra-4,9-dien-17β-ol-3-one, is a
synthetic Synthetic may refer to: Science * Synthetic biology * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic elements, chemical elements that are not naturally found on Earth and therefore have to be created in ...
estrane Estrane is a C18 steroid derivative, with a gonane core. ''Estrenes'' are estrane derivatives that contain a double bond, with an example being nandrolone. ''Estratrienes'' (estrins) are estrane derivatives that contain three double bonds, for i ...
steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...
and a
derivative In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...
of
steroid hormone A steroid hormone is a steroid that acts as a hormone. Steroid hormones can be grouped into two classes: corticosteroids (typically made in the adrenal cortex, hence ''cortico-'') and sex steroids (typically made in the gonads or placenta). Wit ...
s like
progesterone Progesterone (; P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the ma ...
,
cortisol Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal corte ...
, and
testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...
. It has substitutions at the C11β and C17α positions and
double bond In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...
s at the C4(5) and C9(10) positions.


History


1980–1987

In April 1980, as part of a formal research project at the French pharmaceutical company Roussel-Uclaf for the development of glucocorticoid receptor antagonists, endocrinologist
Étienne-Émile Baulieu Étienne-Émile Baulieu (; 12 December 1926 – 30 May 2025) was a French biochemist and endocrinologist who was best known for his research in the field of steroid hormones and their role in reproduction and aging. He has been nicknamed the “ ...
and chemist Georges Teutsch synthesized mifepristone (RU-38486, the 38,486th compound synthesized by Roussel-Uclaf from 1949 to 1980; shortened to RU-486), which was discovered to also be a progesterone receptor antagonist.


In October 1981, Étienne-Émile Baulieu, a consultant to Roussel-Uclaf, arranged tests of its use for medical abortion in 11 women in
Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...
by gynecologist Walter Herrmann at the
University of Geneva The University of Geneva (French: ''Université de Genève'') is a public university, public research university located in Geneva, Switzerland. It was founded in 1559 by French theologian John Calvin as a Theology, theological seminary. It rema ...
's Cantonal Hospital, with successful results announced on 19 April 1982. On 9 October 1987, following worldwide clinical trials in 20,000 women of mifepristone with a
prostaglandin Prostaglandins (PG) are a group of physiology, physiologically active lipid compounds called eicosanoids that have diverse hormone-like effects in animals. Prostaglandins have been found in almost every Tissue (biology), tissue in humans and ot ...
analogue (initially sulprostone or
gemeprost Gemeprost (16, 16-dimethyl-trans-delta2 PGE1 methyl ester) is an analogue of prostaglandin E1. Clinical use It is used as a treatment for obstetric bleeding. It is used with mifepristone to terminate pregnancy up to 24 weeks gestation. Sid ...
, later
misoprostol Misoprostol is a synthetic prostaglandin medication used to prevent and treat stomach and duodenal ulcers, induce labor, cause an abortion, and treat postpartum bleeding due to poor contraction of the uterus. It is taken by mouth when used ...
) for medical abortion, Roussel-Uclaf sought approval in France for their use for medical abortion, with approval announced on 23 September 1988.


1988–1990

On 21 October 1988, in response to antiabortion protests and concerns of majority (54.5%) owner Hoechst AG of Germany, Roussel-Uclaf's executives and board of directors voted 16 to 4 to stop distribution of mifepristone, which they announced on 26 October 1988. Two days later, the French government ordered Roussel-Uclaf to distribute mifepristone in the interests of public health. French Health Minister Claude Évin explained: "I could not permit the abortion debate to deprive women of a product that represents medical progress. From the moment Government approval for the drug was granted, RU-486 became the moral property of women, not just the property of a drug company." Following use by 34,000 women in France from April 1988 to February 1990 of mifepristone distributed free of charge, Roussel-Uclaf began selling Mifegyne (mifepristone) to hospitals in France in February 1990 at a price (negotiated with the French government) of per 600-mg dose.


1991–1996

Mifegyne was subsequently approved in Great Britain in July 1991, and in
Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
in September 1992, but until his retirement in April 1994, Hoechst AG chairman Wolfgang Hilger, a devout
Roman Catholic The Catholic Church (), also known as the Roman Catholic Church, is the largest Christian church, with 1.27 to 1.41 billion baptized Catholics worldwide as of 2025. It is among the world's oldest and largest international institut ...
, blocked any further expansion in availability.

Soon after becoming U.S. President in 1993,
Bill Clinton William Jefferson Clinton (né Blythe III; born August 19, 1946) is an American politician and lawyer who was the 42nd president of the United States from 1993 to 2001. A member of the Democratic Party (United States), Democratic Party, ...
ordered the U.S. Health and Human Services Department to investigate mifepristone's potential as an abortion medication, and also pressured Hoeschst to make the RU-486 medication available in the United States. On 16 May 1994, Roussel-Uclaf announced it was donating without remuneration all rights for medical uses of mifepristone in the United States to the
Population Council The Population Council is an international, nonprofit, non-governmental organization. The Council conducts research in biomedicine, social science, and public health and helps build research capacities in developing countries. One-third of its re ...
, which would then sponsor clinical trials for mifepristone between September 1994 and September 1995. In September 1995, The Population Council licensed mifpristone to Danco Laboratories, which was a new, single-product company that was intended to be resistant to antiabortion boycotts. Danco entered into a manufacturing agreement with Hungarian drug manufacturer Gedeon Richter. In 1996, the US
Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...
(FDA) conditionally licensed RU-486 for early trimester abortion, pending a resolution on some remaining technical and manufacturing issues.


1997–1999

On 8 April 1997, after buying the remaining 43.5% of Roussel-Uclaf stock in early 1997, Hoechst AG ( billion annual revenue) announced the end of its manufacture and sale of Mifegyne ( million annual revenue) and the transfer of all rights for medical uses of mifepristone outside of the United States to Exelgyn, a new single-product company immune to antiabortion boycotts, whose CEO was former Roussel-Uclaf CEO Édouard Sakiz. In 1997, Gideon Richter would withdraw from efforts to manufacture mifepristone in the United States following opposition from pro-life groups, which led to Danco filing a
breach of contract Breach of contract is a legal cause of action and a type of civil wrong, in which a binding agreement or bargained-for exchange is not honored by one or more of the parties to the contract by non-performance or interference with the other part ...
lawsuit. In 1999, Exelgyn won approval of Mifegyne in 11 additional countries, and in 28 more countries over the following decade.


2000–present

In September 2000 Danco Laboratories, a sub-licensee of the Population Council, received approval from the US
Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...
(FDA) to sell mifepristone under the brand name Mifeprex. In 2019, the first generic form of mifepristone in the United States became available, manufactured by GenBioPro. In the early 2000's, several pharmaceutical companies in China were producing mifepristone.


Society and culture

Mifepristone is on the
World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health s ...
. Since 2005, it has been included on the core list, with misoprostol, with a special note "where permitted under national law and where culturally acceptable".


Economics

Cost and availability limit access in many parts of the world.


Frequency of use


United States

Medication abortions voluntarily reported by 33 US states to the
Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...
(CDC) have increased as a percentage of total abortions every year since the approval of mifepristone: 1.0% in 2000, 2.9% in 2001, 5.2% in 2002, 7.9% in 2003, 9.3% in 2004, 9.9% in 2005, 10.6% in 2006, and 13.1% in 2007 (20.3% of those at less than 9 weeks gestation). A
Guttmacher Institute The Guttmacher Institute is a research and policy NGO that aims to improve sexual health and expand reproductive rights worldwide. The organization was started in 1968 as part of Planned Parenthood; it became independent from Planned Parenthood ...
survey of abortion providers estimated that medication abortions accounted for 17% of all abortions and slightly over 25% of abortions before 9 weeks gestation in the United States in 2008 (94% of nonhospital medication abortions used mifepristone and misoprostol, 6% used
methotrexate Methotrexate, formerly known as amethopterin, is a chemotherapy agent and immunosuppressive drug, immune-system suppressant. It is used to treat cancer, autoimmune diseases, and ectopic pregnancy, ectopic pregnancies. Types of cancers it is u ...
and misoprostol).
Medication abortions accounted for 32% of first trimester abortions at
Planned Parenthood The Planned Parenthood Federation of America, Inc. (PPFA), or simply Planned Parenthood, is an American nonprofit organization
clinics in the United States in 2008.
Considering abortions performed in non-hospital facilities, medication abortions accounted for 24% in 2011 and 31% in 2014. In 2014, facilities that provided a relatively small number of abortions (fewer than 400 procedures per year) were more likely to perform them with medication. Medication abortions accounted for 39% of all US abortions in 2017, and 54% in 2020.


Europe

In France, the percentage of medication abortions of all abortions continues to increase: 38% in 2003, 42% in 2004, 44% in 2005, 46% in 2006, 49% in 2007 (vs. 18% in 1996). In England and Wales, 52% of early abortions (less than 9 weeks gestation) in 2009 were medication-based; the percentage of all abortions that are medication-based has increased every year for the past 14 years (from 5% in 1995 to 40% in 2009) and has more than doubled in the last five years. In Scotland, 81.2% of early abortions in 2009 were medication-based (up from 55.8% in 1992 when medication abortion was introduced); the percentage of all abortions that are medication-based has increased every year for the past 17 years (from 16.4% in 1992 to 69.9% in 2009). In Sweden, 85.6% of early abortions and 73.2% of abortions before the end of the 12th week of gestation in 2009 were medication-based; 68.2% of all abortions in 2009 were medication-based. In Great Britain and Sweden, mifepristone is licensed for use with vaginal gemeprost or oral misoprostol. As of 2000, more than 620,000 women in Europe had had medication abortions using a mifepristone regimen. In Denmark, mifepristone was used in between 3,000 and 4,000 of just over 15,000 abortions in 2005.


Legal status


In the United States

Mifepristone was approved for abortion in the United States by the FDA in September 2000. , it was legal and available in all 50 states, Washington, D.C.,
Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...
, and
Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...
. It is a prescription drug, but was not initially available to the public through pharmacies; its distribution is primarily restricted to specially qualified licensed physicians, sold by Danco Laboratories under the brand name Mifeprex. As of September 2021, in 32 states, the drug could only be provided by a licensed physician, and in 19 states, the prescribing clinician was required to be physically in the room with the patient while they are taking the drug. Roussel Uclaf did not seek US approval, so in the United States legal availability was not initially possible. The United States banned importation of mifepristone for personal use in 1989, a decision supported by Roussel Uclaf. In 1994, Roussel Uclaf gave the U.S. drug rights to the Population Council in exchange for immunity from any product liability claims. The Population Council sponsored clinical trials in the United States. The drug went on approvable status from 1996. Production was intended to begin through the Danco Group in 1996, but they withdrew briefly in 1997 due to a corrupt business partner, delaying availability again. In 2016, the US
Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...
(FDA) approved mifepristone, to end a pregnancy through 70 days gestation (70 days or less since the first day of a woman's last menstrual period). The approved dosing regimen is 200 mg of mifepristone taken by mouth (swallowed).  24 to 48 hours after taking mifepristone, 800 mcg (micrograms) of misoprostol is taken buccally (in the cheek pouch), at a location appropriate for the patient. Mifepristone tablets have a marketing authorization in the United States for the treatment of high blood sugar caused by high
cortisol Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal corte ...
levels in the blood (hypercortisolism) in adults with
endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...
Cushing's syndrome Cushing's syndrome is a collection of signs and symptoms due to prolonged exposure to glucocorticoids such as cortisol. Signs and symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, ...
who have
type 2 diabetes mellitus Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ur ...
or
glucose intolerance Prediabetes is a component of metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus. It usually does not cause symptoms, but people with prediabetes often have obesity ( ...
and have failed surgery or cannot have surgery. Due to the
COVID-19 pandemic The COVID-19 pandemic (also known as the coronavirus pandemic and COVID pandemic), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began with an disease outbreak, outbreak of COVID-19 in Wuhan, China, in December ...
, safe access to mifepristone was a concern, and the
American College of Obstetricians and Gynecologists The American College of Obstetricians and Gynecologists (ACOG) is a professional association of physicians specializing in obstetrics and gynecology in the United States. Several Latin American countries are also represented within Districts of ...
among other groups filed a lawsuit to relax the FDA's rule as to allow mifepristone to be acquired from mail-order and retail pharmacies. While the
Fourth Circuit The United States Court of Appeals for the Fourth Circuit (in case citations, 4th Cir.) is a federal court located in Richmond, Virginia, with appellate jurisdiction over the district courts in the following districts: * District of Maryland ...
had granted a preliminary injunction to allow this distribution, the
Supreme Court of the United States The Supreme Court of the United States (SCOTUS) is the highest court in the federal judiciary of the United States. It has ultimate appellate jurisdiction over all Federal tribunals in the United States, U.S. federal court cases, and over Stat ...
issued a stay order in January 2021 to retain the FDA's rule pending the results of the ongoing litigation. On 16 December 2021, the FDA voluntarily adopted a new rule permanently relaxing the requirement that the pill be obtained in person, allowing it to be sent through the mail. A prescription is still required, so that a doctor can screen for risk factors that would make taking the pill unsafe for the mother. In January 2023, the FDA further relaxed rules, allowing any retail pharmacy to become certified to fill mifepristone prescriptions. After regulations on abortion early in pregnancy were ruled constitutional by the 2022 decision ''
Dobbs v. Jackson Women's Health Organization ''Dobbs v. Jackson Women's Health Organization'', 597 U.S. 215 (2022), is a List of landmark court decisions in the United States, landmark decision of the Supreme Court of the United States, United States Supreme Court in which the court held ...
'', some states enacted restrictions on abortions and abortion pills. In January 2023, the
United States Department of Justice The United States Department of Justice (DOJ), also known as the Justice Department, is a United States federal executive departments, federal executive department of the U.S. government that oversees the domestic enforcement of Law of the Unite ...
issued an interpretation of the
Comstock Act The Comstock Act of 1873 is a series of current provisions in federal law that generally criminalize the involvement of the United States Postal Service, its officers, or a common carrier in conveying obscene matter, crime-inciting matter, or ce ...
that it was legal for
United States Postal Service The United States Postal Service (USPS), also known as the Post Office, U.S. Mail, or simply the Postal Service, is an independent agencies of the United States government, independent agency of the executive branch of the federal governmen ...
employees to deliver the pills in any state, because they could not know whether the pills would be used for an abortion or other purposes. In January 2023, GenBioPro filed suit to overturn state laws that prohibit sale of mifepristone, claiming that such laws are invalid because it is a federally approved drug. The argument that state laws seeking to ban or restrict the use of mifepristone are preempted by the FDA's decision to make the drug available is supported by a number of Supreme Court decisions, including opinions by the traditionally more conservative Justices. In March 2023, Wyoming became the first US state to ban the pill. In April 2023, in a lawsuit brought by 17 US states and the
District of Columbia Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and Federal district of the United States, federal district of the United States. The city is on the Potomac River, across from ...
, federal district judge Thomas O. Rice issued a temporary injunction that the FDA should not reduce access to mifepristone in these states and the district. In May 2024, the state of Louisiana classified mifepristone and misoprostol as controlled substances, with penalties for possession without a prescription. The move follows concerns over coerced abortion and has drawn criticism from over 240 doctors in the state.


FDA v. Alliance for Hippocratic Medicine

In April 2023, in the FDA v. Alliance for Hippocratic Medicine lawsuit, federal district judge Matthew J. Kacsmaryk issued a preliminary
injunction An injunction is an equitable remedy in the form of a special court order compelling a party to do or refrain from doing certain acts. It was developed by the English courts of equity but its origins go back to Roman law and the equitable rem ...
suspending the 2000 approval of mifepristone, which would take effect a week later. The Fifth Circuit reversed parts of Kacsmaryk's injunction, but placed a temporary injunction on the 2016 REMS change to mifepristone. On appeal to the Supreme Court, the Court stayed both injunctions on 21 April 2023, with only Justices
Samuel Alito Samuel Anthony Alito Jr. ( ; born April 1, 1950) is an American jurist who serves as an Associate Justice of the Supreme Court of the United States, associate justice of the Supreme Court of the United States. He was Samuel Alito Supreme Court ...
and
Clarence Thomas Clarence Thomas (born June 23, 1948) is an American lawyer and jurist who has served since 1991 as an associate justice of the Supreme Court of the United States. President George H. W. Bush nominated him to succeed Thurgood Marshall. Afte ...
stating their dissent. The stay allowed mifepristone to remain legally available while the lower courts consider the merits of the case. In June 2024, the US Supreme Court unanimously overturned judge Kacsmaryk's Fifth Circuit decision on the grounds that the Alliance for Hippocratic Medicine had no
standing Standing, also referred to as orthostasis, is a position in which the body is held in an upright (orthostatic) position and supported only by the feet. Although seemingly static, the body rocks slightly back and forth from the ankle in the ...
to challenge the FDA's regulations of mifepristone. The Supreme Court ruled that Alliance for Hippocratic Medicine did not demonstrate that they would suffer harm to warrant standing. The Court did not rule on the substance of mifepristone, abortion, or the FDA's procedures.


Subsection H

Some drugs are approved by the FDA under subsection H, which has two subparts. The first sets forth ways to rush experimental drugs, such as aggressive HIV and cancer treatments, to market when speedy approval is deemed vital to the health of potential patients. The second part of subsection H applies to drugs that not only must meet restrictions for use due to safety requirements, but also are required to meet
postmarketing surveillance Postmarketing surveillance (PMS), also known as post market surveillance, is the practice of monitoring the safety of a pharmaceutical drug or medical device after it has been released on the market and is an important part of the science of pharma ...
to establish that the safety results shown in clinical trials are seconded by use in a much wider population. Until December 2021, Mifepristone was approved under the second part of subsection H. The result is that women could not pick the drug up at a
pharmacy Pharmacy is the science and practice of discovering, producing, preparing, dispensing, reviewing and monitoring medications, aiming to ensure the safe, effective, and affordable use of medication, medicines. It is a miscellaneous science as it ...
, but were required to receive it directly from a doctor. Due to the possibility of adverse reactions such as excessive bleeding, which may require a
blood transfusion Blood transfusion is the process of transferring blood products into a person's Circulatory system, circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used ...
, and incomplete abortion, which may require surgical intervention, the drug was only considered safe if a physician who is capable of administering a blood transfusion or a surgical abortion is available to the patient in the event of such emergencies. The approval of mifepristone under subsection H included a
black box warning In the United States, a boxed warning (sometimes "black box warning", colloquially) is a type of warning that appears near the beginning of the package insert for certain prescription drugs, so called because the U.S. Food and Drug Administratio ...
.


European Union

Outside the United States, mifepristone is marketed and distributed by Exelgyn Laboratories under the brand name Mifegyne. It was approved for use in
France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
in 1988 (initial marketing in 1989), 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 Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...
in 1991,
Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
in 1992, then
Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...
,
Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...
,
Denmark Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...
,
Finland Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland to the south, ...
,
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
,
Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...
,
Luxembourg Luxembourg, officially the Grand Duchy of Luxembourg, is a landlocked country in Western Europe. It is bordered by Belgium to the west and north, Germany to the east, and France on the south. Its capital and most populous city, Luxembour ...
,
the Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...
,
Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...
, and
Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...
in 1999. In 2000, it was approved in Norway, Russia and Ukraine. Serbia and Montenegro approved it in 2001,
Belarus Belarus, officially the Republic of Belarus, is a landlocked country in Eastern Europe. It is bordered by Russia to the east and northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Belarus spans an a ...
and
Latvia Latvia, officially the Republic of Latvia, is a country in the Baltic region of Northern Europe. It is one of the three Baltic states, along with Estonia to the north and Lithuania to the south. It borders Russia to the east and Belarus to t ...
in 2002,
Estonia Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Ru ...
in 2003,
Moldova Moldova, officially the Republic of Moldova, is a Landlocked country, landlocked country in Eastern Europe, with an area of and population of 2.42 million. Moldova is bordered by Romania to the west and Ukraine to the north, east, and south. ...
in 2004,
Albania Albania ( ; or ), officially the Republic of Albania (), is a country in Southeast Europe. It is located in the Balkans, on the Adriatic Sea, Adriatic and Ionian Seas within the Mediterranean Sea, and shares land borders with Montenegro to ...
and
Hungary Hungary is a landlocked country in Central Europe. Spanning much of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and ...
in 2005,
Portugal Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...
in 2007,
Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...
in 2008,
Bulgaria Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...
,
Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...
and
Slovenia Slovenia, officially the Republic of Slovenia, is a country in Central Europe. It borders Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the south and southeast, and a short (46.6 km) coastline within the Adriati ...
in 2013. In
Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...
, clinical trials have been constrained by protocols requiring women be hospitalized for three days, but the drug was finally approved on 30 July 2009 (officialized later in the year), despite strong opposition from the Vatican. In Italy, the pill must be prescribed and used in a clinical structure and is not sold at chemists. It was approved in Hungary in 2005, but as of 2005 had not been released on the market yet, and was the target of protests. Mifepristone is licensed in
Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...
for use of abortions up to 12 weeks since it was legalised in 2018. Mifepristone is not available in
Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...
, where abortion is highly restricted. Mifepristone 200 mg tablets (Mifegyne, Mifepristone Linepharma, Medabon) have marketing authorizations in the
European Economic Area The European Economic Area (EEA) was established via the ''Agreement on the European Economic Area'', an international agreement which enables the extension of the European Union's single market to member states of the European Free Trade Asso ...
from the
European Medicines Agency The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of pharmaceutical products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products ...
(EMA) for: * Early first trimester medication abortion when followed by a prostaglandin analog (misoprostol or gemeprost) through 63 days gestational age * Second trimester medication abortion when followed by a prostaglandin analog * Cervical softening and dilation prior to first trimester
surgical abortion Abortion is the early termination of a pregnancy by removal or expulsion of an embryo or fetus. Abortions that occur without intervention are known as miscarriages or "spontaneous abortions", and occur in roughly 30–40% of all pregnanci ...
*
Induction of labor Labor induction is the procedure where a medical professional starts the process of labor ( giving birth) instead of letting it start on its own. Labor may be induced (started) if the health of the mother or the baby is at risk. Induction of lab ...
after fetal death in utero when prostaglandin analogs and
oxytocin Oxytocin is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. Present in animals since early stages of evolution, in humans it plays roles in behavior that include Human bonding, ...
are contraindicated


Other countries

Mifepristone was banned in Australia in 1996. In 2005, a private member's bill was introduced to the Australian Senate to lift the ban and transfer the power of approval to the
Therapeutic Goods Administration The Therapeutic Goods Administration (TGA) is the medicine and therapeutic regulatory agency of the Australian Government. As part of the Department of Health, Disability and Ageing, the TGA regulates the safety, quality, efficacy and advertisi ...
(TGA). The move caused much debate in the Australian media and among politicians. The bill passed the Senate in February 2006, and mifepristone is legal in Australia. It is provided regularly at several specialized abortion clinics per state. Mifepristone 200 mg tablets have marketing authorizations in Australia from the TGA for early first trimester medication abortion when followed by the prostaglandin analog misoprostol through 63 days gestational age and second trimester medication abortion when followed by a prostaglandin analog. In New Zealand, pro-abortion rights doctors established an import company, Istar, and submitted a request for approval to
Medsafe Medsafe, the New Zealand Medicines and Medical Devices Safety Authority, is the medical regulatory body run by the New Zealand Ministry of Health, administering the Medicines Act 1981 and Medicines Regulations 1984. Medsafe employs approximately ...
, the New Zealand pharmaceutical regulatory agency. After a court case brought by Right to Life New Zealand failed, use of mifepristone was permitted. Mifepristone was approved in Israel in 1999. Clinical trials of mifepristone in China began in 1985. In October 1988, China became the first country in the world to approve mifepristone. Chinese organizations tried to purchase mifepristone from
Roussel Uclaf Roussel Uclaf S.A. was a French pharmaceutical company and one of several predecessor companies of today's Sanofi. It was the second largest French pharmaceutical company before it was acquired by Hoechst AG of Frankfurt, Germany in 1997, with p ...
, which refused to sell it to them, so in 1992 China began its own domestic production of mifepristone. In 2000, the cost of medication abortion with mifepristone was higher than surgical abortion and the percentage of medication abortions varied greatly, ranging from 30% to 70% in cities to being almost nonexistent in rural areas. A report from the
United States Embassy The United States has the second largest number of active diplomatic posts of any country in the world after the People's Republic of China, including 272 bilateral posts (embassies and consulates) in 174 countries, as well as 11 permanent miss ...
in Beijing in 2000 said mifepristone had been widely used in Chinese cities for about two years, and that according to press reports, a
black market A black market is a Secrecy, clandestine Market (economics), market or series of transactions that has some aspect of illegality, or is not compliant with an institutional set of rules. If the rule defines the set of goods and services who ...
had developed with many women starting to buy it illegally (without a prescription) from private clinics and drugstores for about , causing Chinese authorities to worry about medical complications from use without physician supervision. In 2001, mifepristone was approved in Taiwan. Vietnam included mifepristone in the National Reproductive Health program in 2002. Mifepristone is approved in only one sub-Saharan African country—South Africa, where it was approved in 2001. It is also approved in one north African country—Tunisia, also in 2001. Mifepristone was approved for use in India in 2002, where medication abortion is referred to as "medical termination of pregnancy". It is only available under medical supervision, not by prescription, due to adverse reactions such as excessive bleeding, and criminal penalties are given for buying or selling it on the black market or over-the-counter at pharmacies. Medication induced abortion used to be available in Canada but on a limited basis using methotrexate and misoprostol. Clinical trials were done in 2000 in various Canadian cities comparing methotrexate to mifepristone, after approbation by the federal government. While both drugs had overall similar results, mifepristone was found to act faster. Health Canada gave approval to mifepristone in July 2015. Initially, its use was limited to seven weeks into a pregnancy, but this was changed to nine weeks in 2017. The previous requirement of written consent from the woman was also ended at the same time. It can be dispensed directly to a patient by a pharmacist or a prescribing health professional. Women are required to have an ultrasound to ensure the pregnancy is not ectopic. Mifepristone was registered for use in Azerbaijan, Georgia, and Uzbekistan in 2002, in Guyana and Moldova in 2004, in Mongolia in 2005, and in Armenia in 2007. Low dose mifepristone tablets for emergency contraception are available directly from a pharmacist without a prescription and with a prescription in China. Low dose mifepristone tablets for emergency contraception are available by prescription in Armenia (Gynepriston), Russia (Agesta, Gynepriston, Mifepristone 72, Negele), Ukraine (Gynepriston), and Vietnam (Mifestad 10, Ciel EC).


Controversy

Many
anti-abortion Anti-abortion movements, also self-styled as pro-life movements, are involved in the abortion debate advocating against the practice of abortion and its Abortion by country, legality. Many anti-abortion movements began as countermovements in r ...
groups in the United States actively campaigned against the approval of mifepristone and continue to actively campaign for its withdrawal. They cite either ethical issues with abortion or safety concerns regarding the drug and the adverse reactions associated with it. Religious and
anti-abortion Anti-abortion movements, also self-styled as pro-life movements, are involved in the abortion debate advocating against the practice of abortion and its Abortion by country, legality. Many anti-abortion movements began as countermovements in r ...
groups outside the United States have also protested mifepristone, especially in Germany and Australia. A court case that originated in Texas in 2023 argued that mifepristone was unsafe and women should no longer be able to order it by mail. This case was won in Texas but was appealed, and in June 2024, the
US Supreme Court The Supreme Court of the United States (SCOTUS) is the highest court in the federal judiciary of the United States. It has ultimate appellate jurisdiction over all Federal tribunals in the United States, U.S. federal court cases, and over Stat ...
ruled unanimously on that case to keep mifepristone available on grounds that those who originally filed the lawsuit did not have standing to file.Supreme Court Rejects Abortion Pill Challenge, Preserving Wide Access to Drug
by Laura Kusisto and Jess Bravin in the Wall Street Journal, June 13, 2024.


Research

The original target for the research group was the discovery and development of compounds with antiglucocorticoid properties. Use of mifepristone as a cervical ripening agent has been described. The medication has been studied as an antiandrogen in the treatment of
prostate cancer Prostate cancer is the neoplasm, uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Abnormal growth of the prostate tissue is usually detected through Screening (medicine), screening tests, ...
. Mifepristone showed no detectable anti-HIV activity in clinical trials. Mifepristone showed initial promise in psychotic major depression, a difficult-to-treat form of depression, but a phase-III clinical trial was terminated early due to lack of efficacy. It has been studied in bipolar disorder, post traumatic stress disorder, and anorexia nervosa.


References


External links


Map and list of mifepristone approvals by year
{{Authority control Abortifacients Alkyne derivatives Anilines Antiglucocorticoids Antiprogestogens CYP3A4 inhibitors CYP17A1 inhibitors Estranes French inventions Medication abortion Pregnane X receptor agonists Selective progesterone receptor modulators Serotonin reuptake inhibitors Steroidal antiandrogens World Health Organization essential medicines Wikipedia medicine articles ready to translate