Anastrozole, sold under the brand name Arimidex among others, is an

antiestrogen Antiestrogens, also known as estrogen antagonists or estrogen blockers, are a class of drugs which prevent estrogens like estradiol from mediating their biological effects in the body. They act by blocking the estrogen receptor (ER) and/or inh ...

ic medication used in addition to other treatments for

breast cancer Breast cancer is a cancer that develops from breast tissue. Signs of breast cancer may include a Breast lump, lump in the breast, a change in breast shape, dimpling of the skin, Milk-rejection sign, milk rejection, fluid coming from the nipp ...

. Specifically it is used for hormone receptor-positive breast cancer. It has also been used to prevent breast cancer in those at high risk. It is taken orally. Common side effects of anastrozole include

hot flash Hot flushes are a form of flushing, often caused by the changing hormone levels that are characteristic of menopause. They are typically experienced as a feeling of intense heat with sweating and rapid heartbeat, and may typically last from t ...

es, altered mood,

joint pain Arthralgia () literally means 'joint pain'. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication Medication (also called medicament, medicine, pharmaceutic ...

, and

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 ...

. Severe side effects include an increased risk of

heart disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina pectoris, angina, myocardial infarction, heart attack), heart failure, ...

and

osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason f ...

. Use during

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 ...

may harm the baby. Anastrozole is in the aromatase-inhibiting family of medications. It works by blocking the

production Production may refer to: Economics and business * Production (economics) * Production, the act of manufacturing goods * Production, in the outline of industrial organization, the act of making products (goods and services) * Production as a stat ...

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 ...

s in the body, and hence has

ic effects. Anastrozole was patented in 1987 and was approved for medical use in 1995. 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 ...

. Anastrozole 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, it was the 179th most commonly prescribed medication in the United States, with more than 2million prescriptions.

Medical uses

Breast cancer

Anastrozole is used in the treatment and prevention of

in women. The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial was of localized breast cancer and women received either anastrozole, the

selective estrogen receptor modulator Selective estrogen receptor modulators (SERMs), also known as estrogen receptor agonists/antagonists (ERAAs), are a class of drugs that act on estrogen receptors (ERs). Compared to pure ER agonists–antagonists (e.g., full agonists and silent ...

tamoxifen Tamoxifen, sold under the brand name Nolvadex among others, is a selective estrogen receptor modulator used to prevent breast cancer in women and men. It is also being studied for other types of cancer. It has been used for Albright syndrome ...

, or both for five years, followed by five years of follow-up. After more than 5 years the group that received anastrozole had better results than the tamoxifen group. The trial suggested that anastrozole is the preferred medical therapy for

postmenopausal Menopause, also known as the climacteric, is the time when menstrual periods permanently stop, marking the end of the reproductive stage for the female human. It typically occurs between the ages of 45 and 55, although the exact timing can ...

women with localized

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 ...

-positive breast cancer.

Early puberty

Anastrozole is used at a dosage of 0.5 to 1 mg/day in combination with the

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 ...

bicalutamide Bicalutamide, sold under the brand name Casodex among others, is an antiandrogen medication that is primarily used to treat prostate cancer. It is typically used together with a gonadotropin-releasing hormone (GnRH) analogue or surgical remo ...

in the treatment of peripheral precocious puberty, for instance due to familial male-limited precocious puberty (testotoxicosis) and

McCune–Albright syndrome McCune–Albright syndrome is a complex genetic disorder affecting the bone, skin and endocrine systems. It is a mosaic disease arising from somatic activating mutations in '' GNAS'', which encodes the alpha-subunit of the Gs heterotrimeric G ...

, in boys.

Available forms

Anastrozole is available in the form of 1 mg

oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or ora ...

tablets. No alternative

form Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens. Form may also refer to: *Form (document), a document (printed or electronic) with spaces in which to write or enter dat ...

s or

routes Route or routes may refer to: * Air route, route structure or airway * GPS route, a series of one or more GPS waypoints * Route (gridiron football), a path run by a wide receiver * Route (command), a program used to configure the routing table * ...

are available.

Contraindications

Contraindication 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 ...

s of anastrozole include

hypersensitivity Hypersensitivity (also called hypersensitivity reaction or intolerance) is an abnormal physiological condition in which there is an undesirable and adverse immune response to an antigen. It is an abnormality in the immune system that causes Imm ...

to anastrozole or any other component of anastrozole formulations,

, and

breastfeeding Breastfeeding, also known as nursing, is the process where breast milk is fed to a child. Infants may suck the milk directly from the breast, or milk may be extracted with a Breast pump, pump and then fed to the infant. The World Health Orga ...

. Hypersensitivity reactions to anastrozole including

anaphylaxis Anaphylaxis (Greek: 'up' + 'guarding') is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of the use of emergency medication on site. It typicall ...

angioedema Angioedema is an area of swelling (edema) of the lower layer of skin and tissue just under the skin or mucous membranes. The swelling may occur in the face, tongue, larynx, abdomen, or arms and legs. Often it is associated with hives, which are ...

, and

urticaria Hives, also known as urticaria, is a kind of skin rash with red or flesh-colored, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and typically ...

have been observed.

Side effects

Common

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 anastrozole (≥10% incidence) include

es,

asthenia Weakness is a symptom of many different medical conditions. The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, ...

arthritis Arthritis is a general medical term used to describe a disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, Joint effusion, swelling, and decreased range of motion of ...

pain Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...

arthralgia Arthralgia () literally means ' joint pain'. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication Medication (also called medicament, medicine, pharmaceuti ...

hypertension Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms i ...

, depression,

and

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 ...

rash A rash is a change of the skin that affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracke ...

bone fracture A bone fracture (abbreviated FRX or Fx, Fx, or #) is a medical condition in which there is a partial or complete break in the continuity of any bone in the body. In more severe cases, the bone may be broken into several fragments, known as a ''c ...

back pain Back pain (Latin: ''dorsalgia'') is pain felt in the back. It may be classified as neck pain (cervical), middle back pain (thoracic), lower back pain (lumbar) or coccydynia (tailbone or sacral pain) based on the segment affected. The lumbar area ...

insomnia Insomnia, also known as sleeplessness, is a sleep disorder where people have difficulty sleeping. They may have difficulty falling asleep, or staying asleep for as long as desired. Insomnia is typically followed by daytime sleepiness, low ene ...

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 ...

bone pain Bone pain (also known medically by several other names) is pain coming from a bone, and is caused by damaging stimuli. It occurs as a result of a wide range of diseases or physical conditions or both, and may severely impair the quality of life. ...

peripheral edema Peripheral edema is edema (accumulation of fluid causing swelling) in tissues perfused by the peripheral vascular system, usually in the lower limbs. In the most dependent parts of the body (those hanging distally), it may be called dependent ede ...

coughing A cough is a sudden expulsion of air through the large breathing passages which can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three ...

dyspnea Shortness of breath (SOB), known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that ...

pharyngitis Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse vo ...

, and

lymphedema Lymphedema, also known as lymphoedema and lymphatic edema, is a condition of localized edema, swelling caused by a compromised lymphatic system. The lymphatic system functions as a critical portion of the body's immune system and returns inters ...

. Serious but rare adverse effects (<0.1% incidence) include

skin reaction A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this sys ...

s such as

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...

ulcer An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughin ...

s, or

blister A blister is a small pocket of body fluid (lymph, serum, plasma, blood, or pus) within the upper layers of the skin, usually caused by forceful rubbing (friction), burning, freezing, chemical exposure or infection. Most blisters are filled ...

allergic reaction Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...

s with swelling of the

face The face is the front of the head that features the eyes, nose and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities may affect th ...

lips The lips are a horizontal pair of soft appendages attached to the jaws and are the most visible part of the mouth of many animals, including humans. Mammal lips are soft, movable and serve to facilitate the ingestion of food (e.g. sucklin ...

tongue The tongue is a Muscle, muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for chewing and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper s ...

, and/or

throat In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebrae. It contains the Human pharynx, pharynx and larynx. An important section of it is the epiglottis, separating the esophagus from the t ...

that may cause difficulty

swallowing Swallowing, also called deglutition or inglutition in scientific and medical contexts, is a physical process of an animal's digestive tract (e.g. that of a human body) that allows for an ingested substance (typically food) to pass from the mou ...

breathing Breathing (spiration or ventilation) is the rhythmical process of moving air into ( inhalation) and out of ( exhalation) the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxy ...

; and abnormal liver function tests as well as

hepatitis Hepatitis is inflammation of the liver parenchyma, liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), Anorexia (symptom), poor appetite ...

Interactions

Anastrozole is thought to have clinically negligible inhibitory effects on the

cytochrome P450 Cytochromes P450 (P450s or CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that mostly, but not exclusively, function as monooxygenases. However, they are not omnipresent; for examp ...

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

CYP1A2 Cytochrome P450 1A2 (abbreviated CYP1A2), a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the human body. In humans, the CYP1A2 enzyme is encoded by the ''CYP1A2'' gene. Function ...

CYP2A6 Cytochrome P450 2A6 (abbreviated CYP2A6) is a member of the cytochrome P450 mixed-function oxidase system, which is involved in the metabolism of xenobiotics in the body. CYP2A6 is the primary enzyme responsible for the oxidation of nicotine an ...

CYP2D6 Cytochrome P450 2D6 (CYP2D6) is an enzyme that in humans is encoded by the ''CYP2D6'' gene. ''CYP2D6'' is primarily expressed in the liver. It is also highly expressed in areas of the central nervous system, including the substantia nigra. CYP2 ...

CYP2C8 Cytochrome P4502C8 (CYP2C8) is a member of the cytochrome P450 mixed-function oxidase system involved in the metabolism of xenobiotics in the body. Cytochrome P4502C8 also possesses epoxygenase activity, i.e. it metabolizes long-chain polyunsat ...

CYP2C9 Cytochrome P450 family 2 subfamily C member 9 (abbreviated CYP2C9) is an enzyme protein. The enzyme is involved in the metabolism, by oxidation, of both xenobiotics, including drugs, and endogenous compounds, including fatty acids. In humans, t ...

, and

CYP2C19 Cytochrome P450 2C19 (abbreviated CYP2C19) is an enzyme protein. It is a member of the CYP2C subfamily of the cytochrome P450 mixed-function oxidase system. This subfamily includes enzymes that catalyze metabolism of xenobiotics, including some ...

. As a result, it is thought that

drug interaction In pharmaceutical sciences, drug interactions occur when a drug's mechanism of action is affected by the concomitant administration of substances such as foods, beverages, or other drugs. A popular example of drug–food interaction is the effect ...

s of anastrozole with cytochrome P450

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

s are unlikely. No clinically significant

s have been reported with anastrozole as of 2003. Anastrozole does not affect circulating levels of

or its 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 ...

''N''-desmethyltamoxifen. However, tamoxifen has been found to decrease

steady-state In systems theory, a system or a process is in a steady state if the variables (called state variables) which define the behavior of the system or the process are unchanging in time. In continuous time, this means that for those properties ''p'' ...

area-under-the-curve levels of anastrozole by 27%. But estradiol levels were not significantly different in the group that received both anastrozole and tamoxifen compared to the anastrozole alone group, so the decrease in anastrozole levels is not thought to be clinically important.

Pharmacology

Pharmacodynamics

Anastrozole works by reversibly binding to the

aromatase Aromatase (), also called estrogen synthetase or estrogen synthase, is an enzyme responsible for a key step in the biosynthesis of estrogens. It is CYP19A1, a member of the cytochrome P450 superfamily, which are monooxygenases that catalyze man ...

, and through

competitive inhibition Competitive inhibition is interruption of a chemistry, chemical pathway owing to one chemical substance inhibiting the effect of another by competing with it for molecular binding, binding or chemical bond, bonding. Any metabolism, metabolic or c ...

blocks the conversion of

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 ...

s to

s in peripheral (extragonadal) tissues. The medication has been found to achieve 96.7% to 97.3% inhibition of aromatase at a dosage of 1 mg/day and 98.1% inhibition of aromatase at a dosage of 10 mg/day in humans. As such, 1 mg/day is considered to be the minimal dosage required to achieve maximal suppression of aromatase with anastrozole. This decrease in aromatase activity results in an at least 85% decrease in estradiol levels in postmenopausal women. Levels of

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 ...

s and other adrenal steroids are unaffected by anastrozole.

Pharmacokinetics

The

bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...

of anastrozole in humans is unknown, but it was found to be well-absorbed in animals. Absorption of anastrozole is linear over a dosage range of 1 to 20 mg/day in humans and does not change with repeated administration.

Food Food is any substance consumed by an organism for Nutrient, nutritional support. Food is usually of plant, animal, or Fungus, fungal origin and contains essential nutrients such as carbohydrates, fats, protein (nutrient), proteins, vitamins, ...

does not significantly influence the extent of absorption of anastrozole.

Peak Peak or The Peak may refer to: Basic meanings Geology * Mountain peak ** Pyramidal peak, a mountaintop that has been sculpted by erosion to form a point Mathematics * Peak hour or rush hour, in traffic congestion * Peak (geometry), an (''n''-3)-d ...

levels of anastrozole occur a median 3 hours after administration, but with a wide range of 2 to 12 hours.

Steady-state In systems theory, a system or a process is in a steady state if the variables (called state variables) which define the behavior of the system or the process are unchanging in time. In continuous time, this means that for those properties ''p'' ...

levels of anastrozole are achieved within 7 to 10 days of continuous administration, with 3.5-fold accumulation. However, maximal suppression of estradiol levels occurs within 3 or 4 days of therapy. Active efflux of anastrozole by

P-glycoprotein P-glycoprotein 1 (permeability glycoprotein, abbreviated as P-gp or Pgp) also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1) or cluster of differentiation 243 (CD243) is an important protein ...

at the

blood–brain barrier The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that regulates the transfer of solutes and chemicals between the circulatory system and the central nervous system ...

has been found to limit the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

penetration of anastrozole in rodents, whereas this was not the case with

letrozole Letrozole, sold under the brand name Femara among others, is an aromatase inhibitor medication that is used in the treatment of breast cancer for post-menopausal women. It was patented in 1986 and approved for medical use in 1996. In 2021, ...

and vorozole. As such, anastrozole may have peripheral selectivity in humans, although this has yet to be confirmed. In any case, estradiol is synthesized peripherally and readily crosses the blood–brain barrier, so anastrozole would still expected to reduce estradiol levels in the central nervous system to a certain degree. The

plasma protein binding Plasma protein binding refers to the degree to which medications attach to blood proteins within the blood plasma. A drug's efficacy may be affected by the degree to which it binds. The less bound a drug is, the more efficiently it can traverse o ...

of anastrozole is 40%. The

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

of anastrozole is by N-dealkylation,

hydroxylation In chemistry, hydroxylation refers to the installation of a hydroxyl group () into an organic compound. Hydroxylations generate alcohols and phenols, which are very common functional groups. Hydroxylation confers some degree of water-solubility ...

, and

glucuronidation Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve gly ...

. Inhibition of aromatase is due to anastrozole itself rather than to

s, with the major circulating metabolite being inactive. 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. ...

of anastrozole is 40 to 50 hours (1.7 to 2.1 days). This allows for convenient once-daily administration. The medication is eliminated predominantly by metabolism in the

liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...

(83 to 85%) but also by residual

excretion Excretion is elimination of metabolic waste, which is an essential process in all organisms. In vertebrates, this is primarily carried out by the lungs, Kidney (vertebrates), kidneys, and skin. This is in contrast with secretion, where the substa ...

by the

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

s unchanged (11%). Anastrozole is excreted primarily in

urine Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...

but also to a lesser extent in

feces Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the ...

Chemistry

Anastrozole is a

nonsteroidal A nonsteroidal compound is a drug that is not a steroid nor a steroid derivative. Nonsteroidal anti-inflammatory drugs (NSAIDs) are distinguished from corticosteroids as a class of anti-inflammatory agents. List of nonsteroidal steroid receptor mo ...

benzyl In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure . Benzyl features a benzene ring () attached to a methylene group (). Nomenclature In IUPAC nomenclature, the prefix benzyl refers to a substituent ...

triazole A triazole is a heterocyclic compound featuring a five-membered ring of two carbon atoms and three nitrogen atoms with molecular formula C2H3N3. Triazoles exhibit substantial Isomer, isomerism, depending on the positioning of the nitrogen atoms w ...

. It is also known as α,α,α',α'-tetramethyl-5-(1''H''-1,2,4-triazol-1-ylmethyl)-''m''-benzenediacetonitrile. Anastrozole is structurally related to

fadrozole Fadrozole (), sold under the brand name Afema (by Novartis), is a selective, nonsteroidal aromatase inhibitor which is or has been used in Japan for the treatment of breast cancer Breast cancer is a cancer that develops from breast tissu ...

, and vorozole, with all being classified as

azole Azoles are a class of five-membered heterocyclic compounds containing a nitrogen atom and at least one other non-carbon atom (i.e. nitrogen, sulfur, or oxygen) as part of the ring. Their names originate from the Hantzsch–Widman nomenclature. Th ...

History

Anastrozole was patented by

Imperial Chemical Industries Imperial Chemical Industries (ICI) was a British Chemical industry, chemical company. It was, for much of its history, the largest manufacturer in Britain. Its headquarters were at Millbank in London. ICI was listed on the London Stock Exchange ...

(ICI) in 1987 and was approved for medical use, specifically the treatment of breast cancer, in 1995.

Society and culture

Generic names

''Anastrozole'' is the generic name of the drug and its , , , and .

Brand names

Anastrozole is primarily sold under the brand name Arimidex. However, it is also marketed under a variety of other brand names throughout the world.

Availability

Anastrozole is available widely throughout the world.

Research

Anastrozole is surprisingly ineffective at treating

gynecomastia Gynecomastia (also spelled gynaecomastia) is the non-cancerous enlargement of one or both breasts in men due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens. Updated by Brent Wisse (10 Novemb ...

, in contrast to

s like

. Anastrozole was under development for the treatment of

female infertility Female infertility refers to infertility in women, which is the inability to Fertilisation, conceive after sexual intercourse. It affects an estimated 48 million women, globally. Female infertility varies widely by region. The highest rates of ...

but did not complete development and hence was never approved for this indication. An anastrozole and

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, ...

vaginal ring Vaginal rings (also known as intravaginal rings, or V-Rings) are polymeric drug delivery devices designed to provide controlled release of drugs for intravaginal administration over extended periods of time. The ring is inserted into the vagina ...

(developmental code name BAY 98–7196) was under development for use as a

hormonal contraceptive Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original ...

and treatment for

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 ...

, but development was discontinued in November 2018 and the formulation was never marketed. Anastrozole increases

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 ...

levels in males and has been studied as an alternative method of

androgen replacement therapy Androgen replacement therapy (ART), often referred to as testosterone replacement therapy (TRT), is a form of hormone therapy in which androgens, often testosterone, are supplemented or replaced. It typically involves the administration of tes ...

in men with

hypogonadism Hypogonadism means diminished functional activity of the human gonad, gonads—the testicles or the ovary, ovaries—that may result in diminished biosynthesis, production of sex hormones. Low androgen (e.g., testosterone) levels are referred t ...

. However, there are concerns about its long-term influence on

bone mineral density Bone density, or bone mineral density, is the amount of bone mineral in bone tissue. The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although clinically it is measured by proxy according to opti ...

in this patient population, as well as other adverse effects.

References

{{Authority control 27-Hydroxylase inhibitors Aromatase inhibitors Drugs developed by AstraZeneca Hormonal antineoplastic drugs Nitriles Peripherally selective drugs Triazoles World Health Organization essential medicines Wikipedia medicine articles ready to translate