Minoxidil is a
medication
Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to medical diagnosis, diagnose, cure, treat, or preventive medicine, prevent disease. Drug therapy (pharmaco ...
used for the treatment of
high blood pressure
Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major ri ...
and
pattern hair loss
Pattern hair loss (also known as androgenetic alopecia (AGA)) is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front h ...
.
It is an
antihypertensive
Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke, heart failure, kidney failure and myocardial infa ...
and a
vasodilator
Vasodilation, also known as vasorelaxation, is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. Blood vessel wal ...
. It 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 ...
by prescription in
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 ...
tablet form and
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 ...
as a
topical
A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ...
liquid or foam.
Medical uses
Minoxidil, when used for
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 ...
, is generally reserved for use in severe hypertension patients who do not respond to at least two agents and a
diuretic
A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics ...
.
Minoxidil is also generally administered with a
loop diuretic
Loop diuretics are pharmacological agents that primarily inhibit the Na-K-Cl cotransporter located on the luminal membrane of cells along the thick ascending limb of the loop of Henle. They are often used for the treatment of hypertension and e ...
to prevent
sodium retention and
potassium retention
Hyperkalemia is an elevated level of potassium (K+) in the blood. Normal potassium levels are between 3.5 and 5.0mmol/L (3.5 and 5.0 mEq/L) with levels above 5.5mmol/L defined as hyperkalemia. Typically hyperkalemia does not cause symptoms. Occ ...
.
It may also cause a
reflex tachycardia and thus is prescribed with a
beta blocker
Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms ( arrhythmia), and to protect the heart from a second heart attack after a first heart attack ( secondary prevention ...
.
Hair loss
Minoxidil, when applied topically, is used for the treatment of hair loss.
It is effective in helping promote hair growth in people with
androgenic alopecia
Pattern hair loss (also known as androgenetic alopecia (AGA)) is a hair loss condition that primarily affects the top and front of the scalp. In male-pattern hair loss (MPHL), the hair loss typically presents itself as either a receding front ...
regardless of sex.
Minoxidil must be used indefinitely for continued support of existing hair follicles and the maintenance of any experienced hair regrowth.
Low-dose oral minoxidil (LDOM) is used
off-label Off-label use is the use of pharmaceutical drugs for an unapproved indication (medicine), indication or in an unapproved age group, dose (biochemistry), dosage, or route of administration. Both prescription drugs and over-the-counter drugs (OTCs) ca ...
against hair loss and to promote hair regrowth.
Oral minoxidil is an effective and well-tolerated treatment alternative for patients having difficulty with topical formulations.
Side effects

Topically applied minoxidil is generally well tolerated, but common side effects include itching of the eyes, general itching, irritation at the treated area, and unwanted hair growth elsewhere on the body.
Alcohol
Alcohol may refer to:
Common uses
* Alcohol (chemistry), a class of compounds
* Ethanol, one of several alcohols, commonly known as alcohol in everyday life
** Alcohol (drug), intoxicant found in alcoholic beverages
** Alcoholic beverage, an alco ...
and
propylene glycol
Propylene glycol ( IUPAC name: propane-1,2-diol) is a viscous, colorless liquid. It is almost odorless and has a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH.
As it contains two alcohol groups, it is classified as a diol. An al ...
present in some topical preparations may dry the scalp, resulting in
dandruff
Dandruff is a skin condition of the scalp. Symptoms include flaking and sometimes mild itchiness. It can result in social or self-esteem problems. A more severe form of the condition, which includes inflammation of the skin, is known as s ...
and
contact dermatitis
Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes ...
.
Side effects of oral minoxidil may include swelling of the face and extremities, rapid heartbeat, or lightheadedness. Cardiac lesions, such as focal
necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...
of the
papillary muscle
The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or ...
and subendocardial areas of the left ventricle, have been observed in laboratory animals treated with minoxidil.
Pseudoacromegaly
Acromegaly is a disorder that results in excess growth of certain parts of the human body. It is caused by excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There ...
is an extremely rare side effect reported with large doses of oral minoxidil.
In 2013 or 2014, a seven-year-old girl was admitted to a children's hospital in
Toulouse
Toulouse (, ; ; ) is a city in southern France, the Prefectures in France, prefecture of the Haute-Garonne department and of the Occitania (administrative region), Occitania region. The city is on the banks of the Garonne, River Garonne, from ...
in France after accidentally ingesting a teaspoon of Alopexy (a brand name for minoxidil in France). The child vomited constantly after ingestion and showed
hypotension
Hypotension, also known as low blood pressure, is a cardiovascular condition characterized by abnormally reduced blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood and is ...
and
tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...
for 40 hours. The authors of the report on the incident stressed that the product should be kept out of reach of children, and urged manufacturers to consider more secure child-resistant packaging.
Pharmacology
Mechanism of action
The
mechanism
Mechanism may refer to:
*Mechanism (economics), a set of rules for a game designed to achieve a certain outcome
**Mechanism design, the study of such mechanisms
*Mechanism (engineering), rigid bodies connected by joints in order to accomplish a ...
by which minoxidil promotes hair growth is not fully understood. Minoxidil is an
adenosine 5'-triphosphate
Adenosine triphosphate (ATP) is a nucleoside triphosphate that provides energy to drive and support many processes in living cells, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all known forms of life, ...
-sensitive
potassium channel opener, causing
hyperpolarization of cell membranes. Theoretically, by widening blood vessels and opening potassium channels, it allows more oxygen, blood, and nutrients to the
follicles. Moreover, minoxidil contains a
nitric oxide
Nitric oxide (nitrogen oxide, nitrogen monooxide, or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes den ...
moiety and may act as a nitric oxide agonist. This may cause follicles in the
telogen phase to shed, which are then replaced by thicker hairs in a new
anagen phase. Minoxidil is a
prodrug
A prodrug is a pharmacologically inactive medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be ...
that is converted by
sulfation
Sulfation (sometimes spelled sulphation in British English) is the chemical reaction that entails the addition of SO3 group. In principle, many sulfations would involve reactions of sulfur trioxide (SO3). In practice, most sulfations are effected ...
via the
sulfotransferase 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 ...
SULT1A1 to its active form,
minoxidil sulfate. The effect of minoxidil is mediated by
adenosine
Adenosine (symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9- glycosidic bond. Adenosine is one of the four nucleoside build ...
, which triggers intracellular signal transduction via both
adenosine A1 receptors and two sub-types of adenosine A
2 receptors (
A2A and
A2B receptors).
Minoxidil acts as an activator of the
Kir6/
SUR2
In molecular biology, the sulfonylurea receptors (SUR) are membrane proteins which are the molecular targets of the sulfonylurea class of antidiabetic drugs whose mechanism of action is to promote insulin release from pancreatic beta cells. Mor ...
channel upon selective binding to SUR2. The expression of
SUR2B in dermal papilla cells might play a role in the production of adenosine.
Minoxidil induces cell growth factors such as VEGF, HGF, IGF-1 and potentiates HGF and IGF-1 actions by the activation of uncoupled
sulfonylurea receptor on the plasma membrane of dermal papilla cells.
A number of ''
in vitro
''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in ...
'' effects of minoxidil have been described in monocultures of various skin and hair follicle cell types including stimulation of cell
proliferation, inhibition of collagen synthesis, and stimulation of
vascular endothelial growth factor
Vascular endothelial growth factor (VEGF, ), originally known as vascular permeability factor (VPF), is a signal protein produced by many cells that stimulates the formation of blood vessels. To be specific, VEGF is a sub-family of growth factors ...
,
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 ...
synthesis and
leukotriene B4
Leukotriene B4 (LTB4) is a leukotriene involved in inflammation. It has been shown to promote insulin resistance in obese mice.
Biochemistry
LTB4 is a leukotriene involved in inflammation. It is produced from leukocytes in response to inflammato ...
expression.
Minoxidil causes a redistribution of cellular iron through its apparent capacity to bind this metal ion. By binding iron in a Fenton-reactive form, intracellular
hydroxyl radical
The hydroxyl radical, •HO, is the neutral form of the hydroxide ion (HO–). Hydroxyl radicals are highly reactive and consequently short-lived; however, they form an important part of radical chemistry. Most notably hydroxyl radicals are pr ...
production would ensue, but hydroxyl would be immediately trapped and scavenged by the minoxidil to generate a nitroxyl radical. It is presumed that this nitroxyl radical will be capable of reduction by
glutathione
Glutathione (GSH, ) is an organic compound with the chemical formula . It is an antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione is capable of preventing damage to important cellular components caused by sources ...
to reform minoxidil. Such a process would cycle until the minoxidil is otherwise metabolized and would result in rapid glutathione depletion with glutathione disulphide formation and therefore with concomitant consumption of
NADPH
Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require N ...
/
NADH
Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an ade ...
and other reducing equivalents. Minoxidil inhibited
PHD
A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...
by interfering with the normal function of
ascorbate
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription die ...
, a
cofactor of the enzyme, leading to a stabilization of
HIF-1α protein and a subsequent activation of
HIF-1. In an in vivo angiogenesis assay, millimolar minoxidil increased blood vessel formation in a VEGF-dependent manner. Minoxidil inhibition of PHD occurs via interrupting
ascorbate
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription die ...
binding to iron. The structural feature of positioning amines adjacent to nitric oxide may confer the ability of millimolar minoxidil to chelate iron, thereby inhibiting PHD. Minoxidil is capable of
tetrahydrobiopterin
Tetrahydrobiopterin (BH4, THB), also known as sapropterin ( INN), is a cofactor of the three aromatic amino acid hydroxylase enzymes, used in the metabolism of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotoni ...
inhibition as a cofactor for nitric oxide synthase.
Minoxidil stimulates
prostaglandin E2 production by activating
COX-1 and
prostaglandin endoperoxide synthase-1 but inhibits
prostacyclin
Prostacyclin (also called prostaglandin I2 or PGI2) is a prostaglandin member of the eicosanoid family of lipid molecules. It inhibits platelet activation and is also an effective vasodilator.
When used as a drug, it is also known as epoprosteno ...
production. Additionally, expression of the
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 ...
E
2 receptor, the most upregulated target gene in the
β-catenin
Catenin beta-1, also known as β-catenin (''beta''-catenin), is a protein that in humans is encoded by the ''CTNNB1'' gene.
β-Catenin is a dual function protein, involved in regulation and coordination of cell–cell adhesion and gene transcr ...
pathway of DP cells, was enhanced by minoxidil, which may enable hair follicles to grow continuously and maintain the anagen phase.
Due to the anti-fibrotic activity of minoxidil inhibition of enzyme
lysyl hydroxylase present in
fibroblast
A fibroblast is a type of cell (biology), biological cell typically with a spindle shape that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and ...
may result in the synthesis of a
hydroxylysine-deficient collagen. Minoxidil can also potentially stimulate
elastogenesis in aortic smooth muscle cells, and in skin fibroblasts in a dose-dependent manner. In hypertensive rats, minoxidil increases elastin levels in the mesenteric, abdominal, and renal arteries by a decrease in
elastase enzyme activity in these tissues. In rats, potassium channel openers decrease calcium influx which inhibits elastin gene transcription through
extracellular signal-regulated kinase 1/2 (
ERK 1/2)-activator protein 1 signaling pathway. ERK 1/2 increases, through elastin gene transcription, adequately cross-linked elastic fiber content synthesized by smooth muscle cells, and decreases the number of cells in the aorta.
Minoxidil possesses
α2-adrenergic receptor 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 ...
activity, stimulates the peripheral
sympathetic nervous system
The sympathetic nervous system (SNS or SANS, sympathetic autonomic nervous system, to differentiate it from the somatic nervous system) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous sy ...
(SNS) by way of carotid and aortic
baroreceptor reflexes. Minoxidil administration also brings an increase in plasma
renin
Renin ( etymology and pronunciation), also known as an angiotensinogenase, is an aspartic protease protein and enzyme secreted by the kidneys that participates in the body's renin-angiotensin-aldosterone system (RAAS)—also known as the reni ...
activity, largely due to the aforementioned activation of the SNS. This activation of the
renin-angiotensin axis further prompts increased biosynthesis of
aldosterone
Aldosterone is the main mineralocorticoid steroid hormone produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. It is essential for sodium conservation in the kidney, salivary glands, sweat glands, and colon. It plays ...
; whereas plasma and urinary aldosterone levels are increased early in the course of treatment with minoxidil, over time these values tend to normalize presumably because of accelerated metabolic clearance of aldosterone in association with hepatic vasodilation.
Minoxidil may be involved in the inhibition of
serotonin
Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, ...
5-HT2 receptors.
Minoxidil might increase blood-tumor barrier permeability in a time-dependent manner by down-regulating
tight junction protein expression and this effect could be related to
ROS/
RhoA
Transforming protein RhoA, also known as Ras homolog family member A (RhoA), is a small GTPase protein in the Rho family of GTPases that in humans is encoded by the ''RHOA'' gene. While the effects of RhoA activity are not all well known, it is ...
/
PI3K
Phosphoinositide 3-kinases (PI3Ks), also called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival and intracellular trafficking, which i ...
/
PKB signal pathway. Minoxidil significantly increases
ROS concentration when compared to untreated cells.
In vitro Minoxidil treatment resulted in a 0.22 fold change for
5α-R2 (p < 0.0001). This antiandrogenic effect of minoxidil, shown by significant downregulation of 5α-R2 gene expression in HaCaT cells, may be one of its mechanisms of action in alopecia.
Minoxidil is less effective when the area of hair loss is large. In addition, its effectiveness has largely been demonstrated in younger men who have experienced hair loss for less than 5 years. Minoxidil use is indicated for central (
vertex) hair loss only. Two clinical studies are being conducted in the US for a medical device that may allow patients to determine if they are likely to benefit from minoxidil therapy.
Conditions such as
Cantú syndrome have been shown to mimic the pharmacological properties of minoxidil.
Chemistry
Minoxidil is an odorless, white to off-white, crystalline powder (crystals from methanol-acetonitrile). When heated to decomposition it emits toxic fumes of nitrogen oxides. It decomposes at 259-261 °C.
Solubility
In chemistry, solubility is the ability of a chemical substance, substance, the solute, to form a solution (chemistry), solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form su ...
(mg/ml):
propylene glycol
Propylene glycol ( IUPAC name: propane-1,2-diol) is a viscous, colorless liquid. It is almost odorless and has a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH.
As it contains two alcohol groups, it is classified as a diol. An al ...
75,
methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...
44,
ethanol
Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...
29,
2-propanol
Isopropyl alcohol (IUPAC name propan-2-ol and also called isopropanol or 2-propanol) is a colorless, flammable, organic compound with a pungent alcoholic odor.
Isopropyl alcohol, an organic polar molecule, is miscible in water, ethanol, an ...
6.7,
dimethylsulfoxide 6.5, water 2.2,
chloroform
Chloroform, or trichloromethane (often abbreviated as TCM), is an organochloride with the formula and a common solvent. It is a volatile, colorless, sweet-smelling, dense liquid produced on a large scale as a precursor to refrigerants and po ...
0.5,
acetone
Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ...
<0.5,
ethyl acetate
Ethyl acetate commonly abbreviated EtOAc, ETAC or EA) is the organic compound with the formula , simplified to . This flammable, colorless liquid has a characteristic sweet smell (similar to pear drops) and is used in glues, nail polish removers, ...
<0.5,
diethyl ether
Diethyl ether, or simply ether, is an organic compound with the chemical formula , sometimes abbreviated as . It is a colourless, highly Volatility (chemistry), volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It belongs ...
<0.5,
benzene
Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hyd ...
<0.5,
acetonitrile
Acetonitrile, often abbreviated MeCN (methyl cyanide), is the chemical compound with the formula and structure . This colourless liquid is the simplest organic nitrile (hydrogen cyanide is a simpler nitrile, but the cyanide anion is not class ...
<0.5.
4.61
Synthesis

Minoxidil, 6-amino-1,2-dihydro-1-hydroxy-2-imino-4-piperidinopyrimidine, is synthesized from
barbituric acid
Barbituric acid or malonylurea or 6-hydroxyuracil is an organic compound based on a pyrimidine heterocyclic skeleton. It is an odorless powder soluble in water. Barbituric acid is the parent compound of barbiturate drugs, although barbituric acid i ...
, the reaction of which with
phosphorus oxychloride
Phosphoryl chloride (commonly called phosphorus oxychloride) is a colourless liquid with the formula . It hydrolyses in moist air releasing phosphoric acid and fumes of hydrogen chloride. It is manufactured industrially on a large scale from phos ...
gives 2,4,6-trichloropyrimidine. Upon reaction with ammonium, this turns into 2,4-diamino-6-chloropyrimidine. Next, the resulting 2,4-diamino-6-chloropyrimidine undergoes a reaction with 2,4-dichlorophenol in the presence of potassium hydroxide, giving 2,4-diamino-6-(2,4-dichlorophenoxy)-pyrimidine. Oxidation of this product with 3-chloroperbenzoic acid gives 2,4-diamino-6-(2,4-dichlorophenoxy)pyrimidine-3-oxide, the 2,4-dichlorophenoxyl group of which is replaced with a piperidine group at high temperature, giving minoxidil.
History
Initial application
Minoxidil was developed in the late 1950s by the
Upjohn Company (later became part of
Pfizer
Pfizer Inc. ( ) is an American Multinational corporation, multinational Pharmaceutical industry, pharmaceutical and biotechnology corporation headquartered at The Spiral (New York City), The Spiral in Manhattan, New York City. Founded in 184 ...
) to treat
ulcers
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 sloughing ...
. In trials using dogs, the compound did not cure ulcers but proved to be a powerful vasodilator. Upjohn synthesized over 200 variations of the compound, including the one it developed in 1963 and named minoxidil.
These studies resulted in the U.S.
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) approving minoxidil (with the brand name Loniten) in the form of oral
tablets to treat
high blood pressure
Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major ri ...
in 1979.
Hair growth
When Upjohn received permission from the U.S.
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 test the new drug as medicine for hypertension they approached Charles A. Chidsey, at the
University of Colorado School of Medicine
The University of Colorado School of Medicine is the medical school of the University of Colorado system. It is located at the Anschutz Medical Campus in Aurora, Colorado, Aurora, Colorado, one of the four University of Colorado campuses, six mil ...
.
He conducted two studies, the second study showing unexpected hair growth. Puzzled by this side-effect, Chidsey consulted Guinter Kahn (who while a dermatology resident at the University of Miami had been the first to observe and report hair development on patients using the minoxidil patch) and discussed the possibility of using minoxidil for treating
hair loss
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarring ...
.
Kahn, along with his colleague Paul J. Grant, had obtained a certain amount of minoxidil and conducted their own research, since they were first to make the side effect observation. Neither Upjohn or Chidsey at the time were aware of the side effect of hair growth.
The two doctors had been experimenting with a 1% solution of minoxidil mixed with several alcohol-based liquids.
Both parties filed patents to use minoxidil for hair loss prevention, which resulted in a decade-long trial between Kahn and Upjohn, which ended with Kahn's name included in a consolidated patent (U.S. #4,596,812 Charles A Chidsey, III and Guinter Kahn) in 1986 and royalties from the company to both Kahn and Grant.
Meanwhile, the effect of minoxidil on hair loss prevention was so clear that in the 1980s physicians were prescribing Loniten
off-label Off-label use is the use of pharmaceutical drugs for an unapproved indication (medicine), indication or in an unapproved age group, dose (biochemistry), dosage, or route of administration. Both prescription drugs and over-the-counter drugs (OTCs) ca ...
to their balding patients.
In August 1988, the FDA approved minoxidil for treating baldness in men
under the brand name "Rogaine" (FDA rejected Upjohn's first choice, Regain, as misleading
[ (Google Books)]). The agency concluded that although "the product will not work for everyone", 39% of the men studied had "moderate to dense hair growth on the crown of the head".
"Men's Rogaine", marketed by Johnson & Johnson went off-patent on January 20, 2006.
In 1991, Upjohn made the product available for women.
"Women's Rogaine", marketed by Johnson & Johnson, went off-patent in February 2014.
Pericardial effusion
Minoxidil has been implicated in causing pericardial effusions including life-threatening cases of cardiac tamponade.
There have been case reports dating back to the 1980s describing this phenomenon, including topical
and oral formulations. The frequency of these occurrences has previously been reported at 3% but the true frequency is difficult to determine as a large proportion of patients in this cohort also had renal insufficiency and may have had an effusion preceding the use of minoxidil.
Society and culture
Economics
In February 1996, the FDA approved both the
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 and the production of
generic formulations of minoxidil.
Upjohn replied to that by lowering prices to half the price of the prescription drug
and by releasing a prescription 5% formula of Rogaine in 1997.
In 1998, a 5% formulation of minoxidil was approved for nonprescription sale by the FDA. The 5% aerosol foam formula was approved for medical use in the US in 2006. The generic versions of the 5% aerosol foam formula were approved in 2017.
In 2017, a study of pharmacy prices in four states for 41 over-the-counter minoxidil products which were "gender-specified" found that the mean price for minoxidil solutions was the same for women and men even though the women's formulations were 2% and the men's were 5%, while the mean price for minoxidil foams, which were all 5%, was 40% higher for women. The authors noted this was the first time
gender-based pricing had been shown for a medication.
Brand names
, Minoxidil is sold under many brand names worldwide, including but not limited to: Alomax, Alopek, Alopexy, Alorexyl, Alostil, Aloxid, Aloxidil, Anagen, Apo-Gain, Axelan, Belohair, Boots Hair Loss Treatment, Botafex, Capillus, Carexidil, Coverit, Da Fei Xin, Dilaine, Dinaxcinco, Dinaxil, Ebersedin, Eminox, Folcare, Follixil, Guayaten, Hair Grow, Hair-Treat, Hairgain, Hairgaine, Hairgrow, Hairway, Headway, Inoxi, Ivix, Keranique, Lacovin, Locemix, Loniten, Lonnoten, Lonolox, Lonoten, Loxon, M E Medic, Maev-Medic, Mandi, Manoxidil, Mantai, Men's Rogaine, Minodil, Minodril, Minostyl, Minovital, Minox, Minoxi, Minoxidil, Minoxidilum, Minoximen, Minoxiten, Minscalp, Mintop, Modil, Morr, Moxidil, Neo-Pruristam, Neocapil, Neoxidil, Nherea, Nioxin, Noxidil, Oxofenil, Pilfud, Pilogro, Pilomin, Piloxidil, Re-Stim, Re-Stim+, Recrea, Regain, Regaine, Regaxidil, Regro, Regroe, Regrou, Regrowth, Relive, Renobell Locion, Reten, Rexidil, Rogaine, Rogan, Scalpmed, Si Bi Shen, Splendora, Superminox, Trefostil, Tricolocion, Tricoplus, Tricovivax, Tricoxane, Trugain, Tugain, Unipexil, Vaxdil, Vius, Women's Regaine, Xenogrow, Xtreme Boost, Xtreme Boost+, Xue Rui, Ylox, and Zeldilon.
It is also sold as a
combination medication
A combination drug is a combination of two or more pharmaceutical drugs as active ingredients combined into a single dosage form, typically as a ''fixed-dose combination'', with each constituent standardized to specifications of a fixed dose. Fix ...
with
amifampridine under the brand names Gainehair and Hair 4 U; and as a combination with
tretinoin
Tretinoin, also known as all-''trans'' retinoic acid (ATRA), is a medication used for the treatment of acne and acute promyelocytic leukemia. For acne, it is applied to the skin as a cream, gel or ointment. For acute promyelocytic leukemia, ...
and
clobetasol under the brand name Sistema GB.
[
]
Research
Minoxidil is being investigated as a potential treatment for ovarian cancer
Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different ...
.
Toxicity to animals
Minoxidil is highly toxic
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...
to dog
The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers. ...
s and cat
The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...
s, even in doses as small as a drop or lick. There are reported cases of cats dying shortly after coming in contact with minimal amounts of the substance.
There is no specific antidote
An antidote is a substance that can counteract a form of poisoning. The term ultimately derives from the Greek term φάρμακον ἀντίδοτον ''(pharmakon antidoton)'', "(medicine) given as a remedy". An older term in English which is ...
, but lipid rescue has been used successfully.
References
External links
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{{Authority control
Amine oxides
Aminopyrimidines
Antihypertensive agents
Hair loss medications
1-Piperidinyl compounds
Potassium channel openers
Prodrugs
Vasodilators
Small-molecule drugs