Hydroxyzine, sold under the brand names Atarax, Vistaril and others, is an

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provide ...

medication. It is used in the treatment of

itchiness Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant s ...

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

anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil Turmoil may refer to: * ''Turmoil'' (1984 video game), a 1984 video game released by Bug-Byte * ''Turmoil'' (2016 video game), a 2016 indie oil tycoon video ...

, and

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

, including that due to

motion sickness Motion sickness occurs due to a difference between actual and expected motion. Symptoms commonly include nausea, vomiting, cold sweat, headache, dizziness, tiredness, loss of appetite, and increased salivation. Complications may rarely include ...

. It is used either

by mouth Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...

injection into a muscle Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have ...

. Common side effects include sleepiness, headache, and a

dry mouth Xerostomia, also known as dry mouth, is dryness in the mouth, which may be associated with a change in the composition of saliva, or reduced salivary flow, or have no identifiable cause. This symptom is very common and is often seen as a side e ...

. Serious side effects may include

QT prolongation Long QT syndrome (LQTS) is a condition affecting repolarization (relaxing) of the heart after a heartbeat, giving rise to an abnormally lengthy QT interval. It results in an increased risk of an irregular heartbeat which can result in fainting, ...

. It is unclear if use during pregnancy or breastfeeding is safe. Hydroxyzine works by blocking the effects of

histamine Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Since histamine was discovered in ...

. It is a

first-generation antihistamine H1 antagonists, also called H1 blockers, are a class of medications that block the action of histamine at the H1 receptor, helping to relieve allergic reactions. Agents where the main therapeutic effect is mediated by negative modulation of ...

in the

piperazine Piperazine () is an organic compound that consists of a six-membered ring containing two nitrogen atoms at opposite positions in the ring. Piperazine exists as small alkaline deliquescent crystals with a saline taste. The piperazines are a broad ...

family of chemicals. It was first

made Made or MADE may refer to: Entertainment Film * ''Made'' (1972 film), United Kingdom * ''Made'' (2001 film), United States Music * ''Made'' (Big Bang album), 2016 * ''Made'' (Hawk Nelson album), 2013 * ''Made'' (Scarface album), 2007 *'' M.A.D.E. ...

Union Chimique Belge UCB (Union Chimique Belge) is a multinational biopharmaceutical company headquartered in Brussels, Belgium. UCB is an international company with revenue of €4.178 billion in 2016 which focuses primarily on research and development, specifical ...

in 1956 and was approved for sale by

Pfizer Pfizer Inc. ( ) is an American multinational pharmaceutical and biotechnology corporation headquartered on 42nd Street in Manhattan, New York City. The company was established in 1849 in New York by two German entrepreneurs, Charles Pfize ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

later that year. In 2020, it was the 70th most commonly prescribed medication in the United States, with more than 10million prescriptions.

Medical uses

Hydroxyzine is used in the treatment of

, and

due to

. A

systematic review A systematic review is a scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from published studies on t ...

concluded that hydroxyzine outperforms placebo in treating generalized anxiety disorder. Insufficient data were available to compare the drug with

benzodiazepines Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, ...

and

buspirone Buspirone, sold under the brand name Buspar, among others, is a medication primarily used to treat anxiety disorders, particularly generalized anxiety disorder. Benefits support its short-term use. It is taken by mouth, and it may take up to fo ...

. Hydroxyzine can also be used for the treatment of

allergic conditions Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermati ...

, such as chronic

urticaria Hives, also known as urticaria, is a kind of skin rash with red, 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 does not leave any long-lasti ...

atopic Atopy is the tendency to produce an exaggerated immunoglobulin E (IgE) immune response to otherwise harmless substances in the environment. Allergic diseases are clinical manifestations of such inappropriate, atopic responses. Atopy may have a ...

or contact dermatoses, and

-mediated

pruritus Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

. These have also been confirmed in both recent and past studies to have no adverse effects on the liver, blood, nervous system, or urinary tract.''United States Food & Drug Administration'', (2004), p1 Use of hydroxyzine for

premedication Premedication is using medication before some other therapy (usually surgery or chemotherapy) to prepare for that forthcoming therapy. Typical examples include premedicating with a sedative or analgesic before surgery; using prophylactic (prevent ...

as a sedative has no effects on tropane alkaloids, such as

atropine Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically giv ...

, but may, following general anesthesia, potentiate

meperidine Pethidine, also known as meperidine and sold under the brand name Demerol among others, is a synthetic opioid pain medication of the phenylpiperidine class. Synthesized in 1938 as a potential anticholinergic agent by the German chemist Otto Eisl ...

and

barbiturate Barbiturates are a class of depressant drugs that are chemically derived from barbituric acid. They are effective when used medically as anxiolytics, hypnotics, and anticonvulsants, but have physical and psychological addiction potential as ...

s, and use in pre-anesthetic adjunctive therapy should be modified depending upon the state of the individual. Hydroxyzine is used as a non-barbiturate tranquilizer and for the treatment of neurological disorders, such as psychoneurosis and other forms of anxiety or tension states. Doses of hydroxyzine hydrochloride used for sleep range from 25 to 100 mg. As with other antihistamine sleep aids, hydroxyzine is usually only prescribed for short term or "as-needed" use since tolerance to the CNS effects of hydroxyzine can develop in as little as a few days.

Contraindications

The administration of hydroxyzine in large amounts by ingestion or intramuscular administration during the onset of pregnancy can cause fetal abnormalities. When administered to pregnant rats, mice and rabbits, hydroxyzine caused abnormalities such as hypogonadism with doses significantly above that of the human therapeutic range.''United States Food & Drug Administration'', (2004), p2 In humans, a significant dose has not yet been established in studies and, by default, the

Food and Drug Administration 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 ...

(FDA) has introduced contraindication guidelines in regard to hydroxyzine. Use by those at risk for or showing previous signs of

hypersensitivity Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. They are usually referred to as an over-reaction of the immune ...

is also contraindicated. Hydroxyzine is contraindicated for intravenous (IV) injection, as it has shown to cause

hemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

. Other contraindications include the administration of hydroxyzine alongside depressants and other compounds which affect the central nervous system; if absolutely necessary, it should only be administered concomitantly in small doses. If administered in small doses with other substances, such as mentioned, then patients should refrain from using dangerous machinery, motor vehicles or any other practice requiring absolute concentration, in accordance with safety law. Studies have also been conducted which show that long-term prescription of hydroxyzine can lead to

tardive dyskinesia Tardive dyskinesia (TD) is a disorder that results in involuntary repetitive body movements, which may include grimacing, sticking out the tongue or smacking the lips. Additionally, there may be rapid jerking movements or slow writhing movemen ...

after years of use, but effects related to dyskinesia have also anecdotally been reported after periods of 7.5 months, such as continual head rolling, lip licking and other forms of

athetoid Athetosis is a symptom characterized by slow, involuntary, convoluted, writhing movements of the fingers, hands, toes, and feet and in some cases, arms, legs, neck and tongue. Movements typical of athetosis are sometimes called ''athetoid'' moveme ...

movement. In certain cases, elderly patients' previous interactions with

phenothiazine Phenothiazine, abbreviated PTZ, is an organic compound that has the formula S(C6H4)2NH and is related to the thiazine-class of heterocyclic compounds. Derivatives of phenothiazine are highly bioactive and have widespread use and rich history. ...

derivatives or pre-existing neuroleptic treatment may have contributed to dyskinesia at the administration of hydroxyzine due to hypersensitivity caused by prolonged treatment, and therefore some contraindication is given for short-term administration of hydroxyzine to those with previous phenothiazine use.

Side effects

Several reactions have been noted in manufacturer guidelines—deep sleep, incoordination, sedation, calmness, and dizziness have been reported in children and adults, as well as others such as

hypotension Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...

tinnitus Tinnitus is the perception of sound when no corresponding external sound is present. Nearly everyone experiences a faint "normal tinnitus" in a completely quiet room; but it is of concern only if it is bothersome, interferes with normal hearin ...

, and headaches.UCB South-Africa, et al., (2004)

Gastrointestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

effects have also been observed, as well as less serious effects such as dryness of the mouth and constipation caused by the mild

antimuscarinic A muscarinic receptor antagonist (MRA) is a type of anticholinergic agent that blocks the activity of the muscarinic acetylcholine receptor. The muscarinic receptor is a protein involved in the transmission of signals through certain parts of th ...

properties of hydroxyzine. Central nervous system effects such as hallucinations or confusion have been observed in rare cases, attributed mostly to overdosage. Such properties have been attributed to hydroxyzine in several cases, particularly in patients treated for neuropsychological disorders, as well as in cases where overdoses have been observed. While there are reports of the "hallucinogenic" or "hypnotic" properties of hydroxyzine, several clinical data trials have not reported such side effects from the sole consumption of hydroxyzine, but rather, have described its overall calming effect described through the stimulation of areas within the

reticular formation The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formation ...

. The hallucinogenic or hypnotic properties have been described as being an additional effect from overall

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

suppression by other CNS agents, such as

lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid ...

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a h ...

. Hydroxyzine exhibits

anxiolytic An anxiolytic (; also antipanic or antianxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxie ...

and

sedative A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but ...

properties in many psychiatric patients. One study showed that patients reported very high levels of subjective sedation when first taking the drug, but that levels of reported sedation decreased markedly over 5-7 days, likely due to CNS receptor desensitization. Other studies have suggested that hydroxyzine acts as an acute hypnotic, reducing

sleep onset latency In sleep science, sleep onset latency (SOL) is the length of time that it takes to accomplish the transition from full wakefulness to sleep, normally to the lightest of the non-REM sleep stages. Sleep latency studies Pioneering Stanford Univers ...

and increasing sleep duration — also showing that some drowsiness did occur. This was observed more in female patients, who also had greater hypnotic response. The use of sedating drugs alongside hydroxyzine can cause oversedation and confusion if administered at high doses—any form of hydroxyzine treatment alongside sedatives should be done under supervision of a doctor. Because of the potential for more severe side effects, this drug is on the list to avoid in the elderly. In 2015, the European Medicines Agency (EMA) announced a small but definite risk of

associated with the use of hydroxyzine. This side effect is more likely to occur in people with pre-existing cardiac disease, or with the use of other medicines known to prolong the QT interval.

Pharmacology

Pharmacodynamics

Hydroxyzine's predominant

mechanism of action In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular tar ...

is as a

potent Potent may refer to: * for the heraldic fur *Warren Potent for the Australian Olympic medalist in shooting See also: *Potency (disambiguation) Potency may refer to: * Potency (pharmacology), a measure of the activity of a drug in a biologica ...

and selective

H₁ receptor

inverse agonist In pharmacology, an inverse agonist is a drug that binds to the same receptor as an agonist but induces a pharmacological response opposite to that of the agonist. A neutral antagonist has no activity in the absence of an agonist or inverse ag ...

. This action is responsible for its

and

effects. Unlike many other first-generation antihistamines, hydroxyzine has a lower

affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Part ...

for the

muscarinic acetylcholine receptor Muscarinic acetylcholine receptors, or mAChRs, are acetylcholine receptors that form G protein-coupled receptor, G protein-coupled receptor complexes in the cell membranes of certain neurons and other Cell (biology), cells. They play several r ...

s, and in accordance, has a lower risk of

anticholinergic Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous syste ...

side effects. In addition to its antihistamine activity, hydroxyzine has also been shown to act more weakly as an antagonist of the serotonin 5-HT_2A receptor, the

dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 8 ...

D₂ receptor, and the α₁-adrenergic receptor. The weak

antiserotonergic A serotonin antagonist, or serotonin receptor antagonist, is a drug used to inhibit the action at serotonin (5-HT) receptors. Types 5-HT2A antagonists Antagonists of the 5-HT2A receptor are sometimes used as atypical antipsychotics (contrast wi ...

effects of hydroxyzine likely underlie its usefulness as an

, as other antihistamines without such properties have not been found to be effective in the treatment of

. Hydroxyzine crosses the blood–brain barrier easily and exerts effects in the

. A

positron emission tomography Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, ...

(PET) study found that brain occupancy of the H₁ receptor was 67.6% for a single 30 mg dose of hydroxyzine. In addition, subjective sleepiness correlated well with the brain H₁ receptor occupancy. PET studies with antihistamines have found that brain H₁ receptor occupancy of more than 50% is associated with a high prevalence of

somnolence Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep ...

and

cognitive decline Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affec ...

, whereas brain H₁ receptor occupancy of less than 20% is considered to be non-sedative.

Pharmacokinetics

Hydroxyzine can be administered orally or via intramuscular injection. When given orally, hydroxyzine is rapidly absorbed from the gastrointestinal tract. The effect of hydroxyzine is notable in 30 minutes. Hydroxyzine is rapidly absorbed and distributed with oral and intramuscular administration, and is metabolized in the liver; the main metabolite (45%),

cetirizine Cetirizine, sold under the brand name Zyrtec among others, is a second-generation antihistamine used to treat allergic rhinitis (hay fever), dermatitis, and urticaria (hives). It is taken by mouth. Effects generally begin within thirty minutes ...

, is formed through oxidation of the alcohol moiety to a carboxylic acid by

alcohol dehydrogenase Alcohol dehydrogenases (ADH) () are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+) to N ...

, and overall effects are observed within one hour of administration. Higher concentrations are found in the skin than in the plasma. Cetirizine, although less sedating, is non- dialyzable and possesses similar antihistamine properties. The other metabolites identified include a ''N''-dealkylated metabolite, and an ''O''-dealkylated 1/16 metabolite with a plasma half-life of 59 hours. These pathways are mediated principally by

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules ( xenobiotics), such as toxins or drugs, so that they can be removed from t ...

and

CYP3A5 Cytochrome P450 3A5 is a protein that in humans is encoded by the ''CYP3A5'' gene. Tissue distribution ''CYP3A5'' encodes a member of the cytochrome P450 superfamily of enzymes. Like most of the cytochrome P450, the CYP3A5 is expressed in the ...

. "In animals, hydroxyzine and its metabolites are excreted in feces via biliary elimination." The T_max of hydroxyzine is about 2.0 hours in both adults and children and its

elimination half-life Biological half-life (also known as elimination half-life, pharmacologic 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 bl ...

is around 20.0 hours in adults (mean age 29.3 years) and 7.1 hours in children. Its elimination half-life is shorter in children compared to adults. In another study, the elimination half-life of hydroxyzine in elderly adults was 29.3 hours. One study found that the elimination half-life of hydroxyzine in adults was as short as 3 hours, but this may have just been due to methodological limitations. Although hydroxyzine has a long elimination half-life and produces antihistamine for as long as 24 hours, the CNS effects of hydroxyzine and other antihistamines with long half-lives seem to diminish after 8 hours. Administration in geriatrics differs from the administration of hydroxyzine in younger patients; according to the FDA, there have not been significant studies made (2004), which include population groups over 65, which provide a distinction between elderly aged patients and other younger groups. Hydroxyzine should be administered carefully in the elderly with consideration given to possible reduced elimination.''United States Food & Drug Administration'', (2004), p3

Chemistry

Hydroxyzine is a member of the

diphenylmethylpiperazine 1-(Diphenylmethyl)piperazine, also known as benzhydrylpiperazine, is a chemical compound and piperazine derivative. It features a piperazine ring with a benzhydryl (di phenylmethyl In organic chemistry, a methyl group is an alkyl derived ...

class of antihistamines. Hydroxyzine is supplied mainly as a

dihydrochloride In chemistry, a hydrochloride is an acid salt resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base (e.g. an amine). An alternative name is chlorhydrate, which comes from French. An archaic alternative na ...

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quanti ...

(hydroxyzine hydrochloride) but also to a lesser extent as an embonate salt (hydroxyzine pamoate). The

molecular weight A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

s of hydroxyzine, hydroxyzine dihydrochloride, and hydroxyzine pamoate are 374.9 g/mol, 447.8 g/mol, and 763.3 g/mol, respectively. Due to their differences in molecular weight, 1 mg hydroxyzine dihydrochloride is equivalent to about 1.7 mg hydroxyzine pamoate.

Analogues

Analogues of hydroxyzine include

buclizine Buclizine is an antihistamine and anticholinergic of the diphenylmethylpiperazine group. It is considered to be an antiemetic, similar to meclizine. In the United Kingdom, buclizine is one of three drugs contained in Migraleve tablets, mar ...

cinnarizine Cinnarizine is an antihistamine and calcium channel blocker of the diphenylmethylpiperazine group. It is prescribed for nausea and vomiting due to motion sickness or other sources such as chemotherapy, vertigo, or Ménière's disease. Cinnarizi ...

cyclizine Cyclizine, sold under a number of brand names, is a medication used to treat and prevent nausea, vomiting and dizziness due to motion sickness or vertigo. It may also be used for nausea after general anaesthesia or that which developed from opio ...

etodroxizine Etodroxizine ( INN) (brand names Vesparax, Drimyl, Indunox, Isonox) is a first-generation antihistamine of the diphenylmethylpiperazine group which is used as a sedative/hypnotic drug A drug is any chemical substance that causes a change in ...

meclizine Meclizine, sold under the brand name Bonine, among others, is an antihistamine used to treat motion sickness and dizziness (vertigo). It is taken by mouth. Effects generally begin in an hour and last for up to a day. Common side effects incl ...

, and pipoxizine among others.

Synthesis

Hydroxyzine is synthesized by the alkylation of 1-(4-chlorobenzhydryl)piperazine with 2-(2-chloroethoxy)ethanol:H. Morren, (1959); H. Morren, (1954); H. Morren, (1954); H. Morren, (1954); H. Morren, (1954); H. Morren, (1954). Hydroxyzine synthesis

Society and culture

Brand names

Hydroxyzine

preparation Preparation may refer to: * Preparation (dental), the method by which a tooth is prepared when removing decay and designing a form that will provide adequate retention for a dental restoration * Preparation (music), treatment of dissonance in tona ...

s require a

doctor's prescription A prescription, often abbreviated or Rx, is a formal communication from a physician or other registered health-care professional to a pharmacist, authorizing them to dispense a specific prescription drug for a specific patient. Historicall ...

. The drug is available in two

formulation Formulation is a term used in various senses in various applications, both the material and the abstract or formal. Its fundamental meaning is the putting together of components in appropriate relationships or structures, according to a formula ...

s, the

pamoate Pamoic acid, also called embonic acid, is a 2-Naphthoic acid derivative. Salts and esters of pamoic acid are known as pamoates or embonates. It can be prepared by the reaction of 3-hydroxy-2-naphthoic acid with formaldehyde. In pharmacology, ...

(anxiolytic) and the

hydrochloride In chemistry, a hydrochloride is an acid salt resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base (e.g. an amine). An alternative name is chlorhydrate, which comes from French. An archaic alternative ...

s (antihistamine). Vistaril, Equipose, Masmoran, and Paxistil are preparations of the pamoate salt, while Atarax, Alamon, Aterax, Durrax, Tran-Q, Orgatrax, Quiess, and Tranquizine are of the hydrochloride salt.

References

External links

* {{Portal bar , Medicine 5-HT2A antagonists Primary alcohols Alpha-1 blockers Antiemetics Anxiolytics Belgian inventions CYP2D6 inhibitors D2 antagonists Ethers H1 receptor antagonists Chlorcyclizines Sedatives Serotonin receptor antagonists Wikipedia medicine articles ready to translate