Norgestrel, sold under the brand name Opill among others, is a

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. ...

which is used in

birth control pill The combined oral contraceptive pill (COCP), often referred to as the birth control pill or colloquially as "the pill", is a type of birth control that is designed to be taken orally by women. It is the oral form of combined hormonal contra ...

s. It is often combined with the

estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...

ethinylestradiol Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. Ethinylestradiol was widely used for various indications such as the treatment of menopausal symptoms, gynecological ...

, marketed as Ovral. It is also used in

menopausal hormone therapy Hormone replacement therapy (HRT), also known as menopausal hormone therapy or postmenopausal hormone therapy, is a form of hormone therapy used to treat symptoms associated with female menopause. Effects of menopause can include symptoms such ...

. It is taken

by mouth Oral administration is a route of administration whereby a substance is taken through the Human mouth, mouth, swallowed, and then processed via the digestive system. This is a common route of administration for many medications. Oral administ ...

Side effect In medicine, a side effect is an effect of the use of a medicinal drug or other treatment, usually adverse but sometimes beneficial, that is unintended. Herbal and traditional medicines also have side effects. A drug or procedure usually use ...

s of norgestrel include menstrual irregularities,

headache A headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of Depression (mood), depression in those with severe ...

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 ...

, and

breast tenderness Breast pain is the symptom of discomfort in either one or both breasts. Pain in both breasts is often described as ''breast tenderness'', is usually associated with the menstrual period and is not serious. Pain that involves only one part of a ...

. The most common side effects of the norgestrel include irregular bleeding, headaches, dizziness, nausea, increased appetite, abdominal pain, cramps, or bloating. Norgestrel is a

, or 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 ...

progestogen Progestogens, also sometimes written progestins, progestagens or gestagens, are a class of natural or synthetic steroid hormones that bind to and activate the progesterone receptors (PR). Progesterone is the major and most important progestoge ...

, and hence is an

agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

of the

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 ...

, the

biological target A biological target is anything within a living organism to which some other entity (like an endogenous ligand or a drug) is directed and/or binds, resulting in a change in its behavior or function. Examples of common classes of biological targets ...

of progestogens 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 ...

. It has weak

androgen An androgen (from Greek ''andr-'', the stem of the word meaning ) is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes ...

ic activity and no other important hormonal activity. Norgestrel was patented in 1961 and came into medical use, specifically in birth control pills, in 1966. It was subsequently introduced for use in menopausal hormone therapy as well. Norgestrel is sometimes referred to as a "second-generation" progestin. It is marketed widely throughout the world. Norgestrel is available as a

generic medication A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active ch ...

. In 2022, the version with

was the 264th most commonly prescribed medication in the United States, with more than 1million prescriptions. In July 2023, 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 norgestrel for

over-the-counter Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid pres ...

sale.

Medical uses

Norgestrel is used in combination with

or quinestrol in combined birth control pills, alone in progestogen-only birth control pills, and in combination with

estradiol Estradiol (E2), also called oestrogen, oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of female reproductive cycles such as estrous and menstrual cycles. Estradiol is responsible ...

conjugated estrogens Conjugated estrogens (CEs), or conjugated equine estrogens (CEEs), sold under the brand name Premarin among others, is an estrogen medication which is used in menopausal hormone therapy and for various other indications. It is a mixture of th ...

. It has also been used as 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), ...

in the Yuzpe regimen.

Side effects

Pharmacology

Pharmacodynamics

Norgestrel is a

, or an

of the

. The

biological activity In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or ...

of norgestrel lies in the ''levo''

enantiomer In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities whi ...

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, ...

, whereas the ''dextro'' isomer is inactive. As such, norgestrel is identical in its hormonal activity to levonorgestrel except that it is half as potent by weight. Levonorgestrel, and by extension norgestrel, have some

ic activity, but no

ic,

antimineralocorticoid A mineralocorticoid receptor antagonist (MRA or MCRA) or aldosterone antagonist, is a diuretic drug which receptor antagonist, antagonizes the action of aldosterone at mineralocorticoid receptors. This group of drugs is often used as adjunctive t ...

, or

glucocorticoid Glucocorticoids (or, less commonly, glucocorticosteroids) are a class of corticosteroids, which are a class of steroid hormones. Glucocorticoids are corticosteroids that bind to the glucocorticoid receptor that is present in almost every vertebra ...

activity. The

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 ...

-inhibiting dose of norgestrel appears to be greater than 75μg/day, as ovulation occurred in 50 to 75% of cycles with this dosage of norgestrel in studies. The ovulation-inhibiting dosage of levonorgestrel, which is twice as potent as norgestrel, is approximately 50 to 60μg/day. One review lists the ovulation-inhibiting dose of norgestrel as 100μg/day. The endometrial transformation dose of norgestrel is listed as 12mg per cycle and the menstrual delay test dose of norgestrel is listed as 0.5 to 2mg/day.

Pharmacokinetics

The

pharmacokinetics Pharmacokinetics (from Ancient Greek ''pharmakon'' "drug" and ''kinetikos'' "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to describing how the body affects a specific su ...

of norgestrel have been reviewed.

Chemistry

Norgestrel, also known as ''rac''-13-ethyl-17α-ethynyl-19-nortestosterone or as ''rac''-13-ethyl-17α-ethynylestr-4-en-17β-ol-3-one, is a

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 ...

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 is a

racemic mixture In chemistry, a racemic mixture or racemate () is a mixture that has equal amounts (50:50) of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as r ...

stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in ...

s dextronorgestrel (the C13α isomer; l-norgestrel, L-norgestrel, or (+)-norgestrel) and

(the C13β isomer; d-norgestrel, D-norgestrel, or (–)-norgestrel), the former of which is inactive (making norgestrel exactly half as potent as levonorgestrel). Norgestrel is more specifically a derivative of

norethisterone Norethisterone, also known as norethindrone and sold under the brand name Norlutin among others, is a progestin medication used in birth control pills, menopausal hormone therapy, and for the treatment of gynecological disorders. The medicatio ...

(17α-ethynyl-19-nortestosterone) and is a member of the

gonane Gonane (cyclopentanoperhydrophenanthrene) is a chemical compound with formula , whose structure consists of four hydrocarbon rings fused together: three cyclohexane units and one cyclopentane. It can also be viewed as the result of fusing a cyc ...

(18-methylestrane) subgroup of the

19-nortestosterone Nandrolone, also known as 19-nortestosterone, is an endogenous androgen. It is also an anabolic steroid (AAS) which is medically used in the form of esters such as nandrolone decanoate (brand name Deca-Durabolin) and nandrolone phenylpropionat ...

family of progestins.

Synthesis

Chemical syntheses of norgestrel have been published.

History

Norgestrel was first introduced, as a birth control pill in combination with

, under the brand name Eugynon in Germany in 1966. It was subsequently marketed as a combined birth control pill with ethinylestradiol in the United States under the brand name Ovral in 1968, and was marketed in many other countries as well. The contraceptive efficacy of norgestrel was established in the U.S. with the original approval for prescription use in 1973. In July 2023, the

FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

approved norgestrel for

sale. The FDA granted the approval to Laboratoire HRA Pharma which was acquired by Perrigo Company plc.

Society and culture

Generic names

Norgestrel is the generic name of the drug and its international nonproprietary name, United States Adopted Name,

United States Pharmacopeia The ''United States Pharmacopeia'' (''USP'') is a pharmacopeia (compendium of drug information) for the United States published annually by the over 200-year old United States Pharmacopeial Convention (usually also called the USP), a nonprofi ...

British Approved Name A British Approved Name (BAN) is the official, non-proprietary, or generic name given to a pharmaceutical substance, as defined in the British Pharmacopoeia (BP). The BAN is also the official name used in some countries around the world, because ...

, Dénomination Commune Française, Denominazione Comune Italiana, and

Japanese Accepted Name A (JAN) is the official non-proprietary or generic name given to a pharmaceutical substance by the Government of Japan. See also * International Nonproprietary Name (INN) * United States Adopted Name (USAN) * British Approved Name (BAN) * ...

. It is also known as dl-norgestrel, DL-norgestrel, or (±)-norgestrel.

Brand names

Norgestrel is marketed under a variety of brand names including Cyclacur, Cryselle, Cyclo-Progynova, Duoluton, Elinest, Eugynon, Microgynon, Lo/Ovral, Low-Ogestrel, Logynon, Microlut, Minicon, Nordette, Neogest, Opill, Ogestrel, Ovral, Ovran, Ovranette, Ovrette, Planovar, Prempak, Progyluton, and Trinordiol among others.

References

{{Authority control Tertiary alcohols Ethynyl compounds Anabolic–androgenic steroids Estranes Hormonal contraception Ketones Progestogens