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Encyclopedia > H1 antagonist
The correct title of this article is H1 antagonist. It features superscript or subscript characters that are substituted or omitted because of technical limitations.

An H1 antagonist is a histamine antagonist of the H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions. Agents where the main therapeutic effect is mediated by negative modulation of histamine receptors are termed antihistamines - other agents may have antihistaminergic action but are not true antihistamines. This article is about the term superscript as used in typography. ... A subscript is a number, figure, or indicator that appears below the normal line of type, typically used in a formula, mathematical expression, or description of a chemical compound. ... A histamine antagonist is an agent which serves to inhibit the release or action of histamine. ... RNA expression pattern Orthologs Human Mouse Entrez Ensembl Uniprot Refseq Location Pubmed search The H1 receptor is a histamine receptor, and thus an important target for clinically important drugs, and is likely one of the most important receptors for modulating mammalian circadian cycles. ... This article or section does not cite any references or sources. ... Allergy is an abnormal reaction to a substance foreign to the body that is acquired, predictable and rapid. ...


In common use, the term "antihistamine" refers only to H1 antagonists, also known as H1-receptor antagonists and H1-antihistamines. It has been discovered that these H1-antihistamines are actually inverse agonists at the histamine H1-receptor, rather than antagonists per se. [1] In pharmacology, an inverse agonist is an agent which binds to the same receptor binding-site as an agonist for that receptor but exerts the opposite pharmacological effect. ... Antagonists will block the binding of an agonist at a receptor molecule, inhibiting the signal produced by a receptor-agonist coupling. ...

Contents

Pharmacology

In allergic reactions, an allergen (a type of antigen) interacts with and cross-links surface IgE antibodies on mast cells and basophils. Once the mast cell-antibody-antigen complex is formed, a complex series of events occurs that eventually leads to cell degranulation and the release of histamine (and other chemical mediators) from the mast cell or basophil. Once released, histamine can react with local or widespread tissues through histamine receptors. An allergen is any substance (antigen), most often eaten or inhaled, that is recognized by the immune system and causes an allergic reaction. ... An antigen or immunogen is a molecule that stimulates an immune response. ... Each antibody binds to a specific antigen; an interaction similar to a lock and key. ... Mast cells A mast cell (or mastocyte) is a resident cell of areolar connective tissue (loose connective tissue) that contains many granules rich in histamine and heparin. ... Categories: Wikipedia cleanup | Biology stubs | Blood and immune system cells ... The degranulation process in a Mast cell. ... The histamine receptors are a class of G-protein coupled receptors with histamine as their endogenous ligand. ...


Histamine, acting on H1-receptors, produces pruritus, vasodilatation, hypotension, flushing, headache, tachycardia, bronchoconstriction, increase in vascular permeability, potentiation of pain, and more. [2] For other uses, see Itch (disambiguation). ... A vasodilator is a drug or chemical that relaxes the smooth muscle in blood vessels, which causes them to dilate. ... In physiology and medicine, hypotension refers to an abnormally low blood pressure. ... For a person to flush is to become markedly red in the face and often other areas of the skin, from various physiological conditions. ... A headache (cephalgia in medical terminology) is a condition of pain in the head; sometimes neck or upper back pain may also be interpreted as a headache. ... This article or section does not cite any references or sources. ... Bronchoconstriction is the constriction of the airways in the lungs due to the tighting of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath. ... Vascular permeability characterizes the capacity of a blood vessel wall to pass through small molecules (ions, water, nutrients) or even whole cells (lymphocytes on their way to the site of inflammation). ... Look up Pain in Wiktionary, the free dictionary. ...


While H1-antihistamines help against these effects, they work only if taken before contact with the allergen. In severe allergies, such as anaphylaxis or angioedema, these effects may be so severe as to be life-threatening. Additional administration of epinephrine, often in the form of an autoinjector (Epi-pen), is required by people with such hypersensitivities. Anaphylaxis is an acute systemic (multi-system) and severe Type I Hypersensitivity allergic reaction in humans and other mammals. ... Angioedema (BE: angiooedema), also known by its eponym Quinckes edema, is the rapid swelling (edema) of the skin, mucosa and submucosal tissues. ... Adrenaline redirects here. ... A 0. ...


Clinical use of H1-antihistamines

Indications

H1-antihistamines are clinically used in the treatment of histamine-mediated allergic conditions. Specifically, these indications may include: [3]

H1-antihistamines can be administered topically (through the skin, nose, or eyes) or systemically, based on the nature of the allergic condition. Rhinitis is the medical term describing irritation and inflammation of the nose. ... This article is about the organ. ... Contact dermatitis is a term for a skin reaction resulting from exposure to allergens or irritants. ... Angioedema (BE: angiooedema), also known by its eponym Quinckes edema, is the rapid swelling (edema) of the skin, mucosa and submucosal tissues. ... An itch (Latin: pruritus) is a sensation felt on an area of skin that makes a person or animal want to scratch it. ... Anaphylaxis is an acute systemic (multi-system) and severe Type I Hypersensitivity allergic reaction in humans and other mammals. ... This article is about the organ. ... For other uses, see Nose (disambiguation). ... For other uses, see Eye (disambiguation). ...


The authors of the American College of Chest Physicians Updates on Cough Guidelines (2006) recommend that, for cough associated with the common cold, first-generation antihistamine-decongestants are more effective than newer, non-sedating antihistamines. First-generation antihistamines include diphenhydramine (Benadryl); carbinoxamine (Clistin); clemastine (Tavist); chlorpheniramine (Chlor-Trimeton) and brompheniramine (Dimetane). However, it is important to note that a 1955 study of "antihistaminic drugs for colds," carried out by the U.S. Army Medical Corps, reported that "there was no significant difference in the proportion of cures reported by patients receiving oral antihistaminic drugs and those receiving oral placebos. Furthermore, essentially the same proportion of patients reported no benefit from either type of treatment."[4] Diphenhydramine hydrochloride (trade name Benadryl as produced by Johnson & Johnson, or Dimedrol outside the U.S. & Canada. ...


Adverse drug reactions

Adverse drug reactions are most commonly associated with the first-generation H1-antihistamines. This is due to their relative lack of selectivity for the H1-receptor. An adverse drug reaction (abbreviated ADR) or adverse drug event (abbreviated ADE) is an expression that describes the unwanted, negative consequences associated with the use of given medications. ...


The most common adverse effect is sedation; this "side-effect" is utilized in many OTC sleeping-aid preparations. Other common adverse effects in first-generation H1-antihistamines include dizziness, tinnitus, blurred vision, euphoria, uncoordination, anxiety, insomnia, tremor, nausea and vomiting, constipation, diarrhea, dry mouth, and dry cough. Infrequent adverse effects include urinary retention, palpitations, hypotension, headache, hallucination, and psychosis. [3] Over-the-counter substances, also abbreviated OTC, are drugs and other medical remedies that may be sold without a prescription and without a visit to a medical professional, in contrast to prescription only medicines (POM). ... Tinnitus (pronounced or ,[1] from the Latin word for ringing[2]) is the perception of sound in the human ear in the absence of corresponding external sound(s). ... Euphoria (Greek ) is a medically recognized emotional state related to happiness. ... Anxiety is a physiological state characterized by cognitive, somatic, emotional, and behavioral components[1]. These components combine to create the feelings that we typically recognize as anger and known as fear, apprehension, or worry. ... This article is about the sleeping disorder. ... For other uses, see Nausea (disambiguation). ... Constipation, costiveness, or irregularity, is a condition of the digestive system where a person (or animal) experiences hard feces that are difficult to egest. ... In medicine, diarrhea, also spelled diarrhoea (see spelling differences), refers to frequent loose or liquid bowel movements. ... A palpitation is an abnormal awareness of the beating of the heart, whether it is too slow, too fast, irregular, or at its normal frequency. ... In physiology and medicine, hypotension refers to an abnormally low blood pressure. ... A headache (cephalgia in medical terminology) is a condition of pain in the head; sometimes neck or upper back pain may also be interpreted as a headache. ... A hallucination is a perception in the absence of a stimulus that the person may or may not believe is real. ... For other uses, see Psychosis (disambiguation). ...


The newer second-generation H1-antihistamines are far more selective for peripheral histamine H1-receptors and have a far improved tolerability profile compared to the first-generation agents. The most common adverse effects noted for second-generation agents include drowsiness, fatigue, headache, nausea and dry mouth. [3]


First-generation (non-selective, classical)

These are the oldest H1-antihistaminergic drugs and are relatively inexpensive and widely available. They are effective in the relief of allergic symptoms, but are typically moderately to highly-potent muscarinic acetylcholine receptor-antagonists (anticholinergic) agents as well. These agents also commonly have action at α-adrenergic receptors and/or 5-HT receptors. This lack of receptor-selectivity is the basis of the poor tolerability-profile of some of these agents, especially compared with the second-generation H1-antihistamines. Patient response and occurrence of adverse drug reactions vary greatly between classes and between agents within classes. An acetylcholine receptor (abbreviated AChR) is an integral membrane protein that responds to the binding of the neurotransmitter acetylcholine. ... An anticholinergic agent is a member of a class of pharmaceutical compounds which serve to reduce the effects mediated by acetylcholine in the central nervous system and peripheral nervous system. ... Epinephrine Norepinephrine The adrenergic receptors (or adrenoceptors) are a class of G protein-coupled receptors that are targets of the catecholamines. ... In the field of neurochemistry, 5-HT receptors are receptors for the neurotransmitter and peripheral signal mediator serotonin, also known as 5-hydroxytryptamine or 5-HT. 5-HT receptors are located on the cell membrane of nerve cells and other cell types in animals and mediate the effects of serotonin...


Classes

The first H1-antihistamine discovered was piperoxan, by Ernest Fourneau and Daniel Bovet (1933) in their efforts to develop a guinea pig animal-model for anaphylaxis at Ryerson University.[5] Bovet went on to win the 1957 Nobel Prize in Physiology or Medicine for his contribution. Following their discovery, the first-generation H1-antihistamines were developed in the following decades. They can be classified on the basis of chemical structure, and agents within these groups have similar properties. Daniel Bovet (March 23, 1907 – April 8, 1992) was a Swiss-born Italian pharmacologist who won the 1957 Nobel Prize in Physiology or Medicine for his discovery of drugs that block the actions of specific neurotransmitters. ... For other uses, see Guinea pig (disambiguation). ... Anaphylaxis is an acute systemic (multi-system) and severe Type I Hypersensitivity allergic reaction in humans and other mammals. ... Ryerson University is a public university located in downtown Toronto, Canada. ... Emil Adolf von Behring was the first person to receive the Nobel Prize in Physiology or Medicine, for his work on the treatment of diphtheria. ...

Class Description Examples
Ethylenediamines Ethylenediamines were the first group of clinically-effective H1-antihistamines developed.
Ethanolamines Diphenhydramine was the prototypical agent in this group. Significant anticholinergic adverse effects, as well as sedation, are observed in this group but the incidence of gastrointestinal adverse effects is relatively low. [3] [6]
Alkylamines The isomerism is a significant factor in the activity of the agents in this group. E-triprolidine, for example, is 1000-fold more potent than Z-triprolidine. This difference relates to the positioning and fit of the molecules in the histamine H1-receptor binding site. [6] Alkylamines are considered to have relatively fewer sedative and gastrointestinal adverse effects, but relatively greater incidence of paradoxical CNS stimulation. [3]
Piperazines These compounds are structurally-related to the ethylenediamines and the ethanolamines, and produce significant anticholinergic adverse effects. Compounds from this group are often used for motion sickness, vertigo, nausea, and vomiting. The second-generation H1-antihistamine cetirizine also belongs to this chemical group. [6]
Tricyclics and Tetracyclics These compounds differ from the phenothiazine antipsychotics in the ring-substitution and chain characteristics. (Nelson, 2002) They are also structurally-related to the tricyclic antidepressants (and tetracyclics), explaining the H1-antihistaminergic adverse effects of those three drug classes and also the poor tolerability profile of tricyclic H1-antihistamines. The second-generation H1-antihistamine loratadine was derived from compounds in this group.

Mepyramine[1] is a first generation antihistamine. ... Antazoline is an antihistamine used to relieve nasal congestion and in eye drops, usually in combination with naphazoline, to relieve the symptoms of allergic conjunctivitis. ... An anticholinergic agent is a member of a class of pharmaceutical compounds which serve to reduce the effects mediated by acetylcholine in the central nervous system and peripheral nervous system. ... Diphenhydramine hydrochloride (trade name Benadryl as produced by Johnson & Johnson, or Dimedrol outside the U.S. & Canada. ... Carbinoxamine is an antihistamine. ... This article or section may be confusing or unclear for some readers, and should be edited to rectify this. ... Clemastine is an over-the-counter antihistamine sold in the United States under the name Tavist. ... This article does not cite any references or sources. ... In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of chemical bonds between atoms, but in which the atoms are arranged differently (analogous to a chemical anagram). ... A diagram showing the CNS: 1. ... Pheniramine maleate is an antihistamine used to treat allergic conditions such as hay fever or urticaria. ... Chlorphenamine (INN) or chlorpheniramine (USAN, former BAN), commonly marketed as its salt chlorphenamine maleate (CPM), is first-generation antihistamine used in the prevention of the symptoms of allergic conditions such as rhinitis and urticaria. ... Dexchlorpheniramine maleate (Polaramine®, Schering) is an antihistamine used to treat allergic conditions such as hay fever or urticaria. ... Categories: Stub | Antihistamines ... Triprolidine hydrochloride is an over-the-counter antihistamine. ... An anticholinergic agent is a member of a class of pharmaceutical compounds which serve to reduce the effects mediated by acetylcholine in the central nervous system and peripheral nervous system. ... Cetirizine hydrochloride (IPA sɛ.ˈtɪɹ.ɪ.ˌzin) is a major metabolite of hydroxyzine, and a racemic selective H1 receptor antagonist used in the treatment of allergies, hay fever, angioedema, and urticaria. ... Cyclizine is an antihistamine drug used to treat nausea, vomiting and dizziness associated with motion sickness, vertigo and post-operative following administration of general anaesthesia and opioids. ... This article belongs in one or more categories. ... Hydroxyzine (pronounced ) is a first-generation antihistamine, of the piperazine class that is an H1 receptor antagonist. ... Meclizine (proposed INN is meclozine) is an antihistamine, considered to be an antiemetic. ... Phenothiazines are the largest of the 5 main classes of antipsychotic drugs. ... The term antipsychotic is applied to a group of drugs used to treat psychosis. ... Chemical structure of the tricyclic antidepressant amitriptyline. ... There are also several chemically unrelated tetracyclic antibiotics based on Tetracycline. ... Promethazine is a first-generation H1 receptor antagonist antihistamine and antiemetic medication. ... Alimemazine (INN), also known as trimeprazine (former BAN and USAN; trade names Nedeltran, Panectyl, Repeltin, Therafene, Theralen, Theralene, Vallergan, Vanectyl, or Temaril), commonly provided as a tartrate salt, is a phenothiazine derivative that is used as an antipruritic (it prevents itching from causes such as eczema or poison ivy, by... Cyproheptadine (usually as cyproheptadine hydrochloride, trade name Periactin) is an antihistaminic and antiserotonergic agent. ... Azatadine is an antihistamine. ... Ketotifen fumarate (Zaditor®) is an H1-antihistamine available in two forms. ...

Common structural features

  • Two aromatic rings, connected to a central carbon, nitrogen or CO
  • Spacer between the central X and the amine, usually 2-3 carbons in length, linear, ring, branched, saturated or unsaturated
  • Amine is substituted with small alkyl groups, e.g., CH3


X = N, R1 = R2 = small alkyl groups
X = C
X = CO Image File history File links Antihistamine. ...

  • Chirality at X can increase both the potency and selectivity for H1-receptors
  • For maximum potency, the two aromatic rings should be orientated in different planes
    • for example, tricyclic ring system is slightly puckered and the two aromatic rings lie in different geometrical planes, giving the drug a very high potency.

Second-generation and third-generation (selective, non-sedating)

Second generation H1-antihistamines are newer drugs that are much more selective for peripheral H1 receptors in preference to the central nervous system histaminergic and cholinergic receptors. This selectivity significantly reduces the occurrence of adverse drug reactions compared with first-generation agents, while still providing effective relief of allergic conditions. A diagram showing the CNS: 1. ...


Third-generation H1-antihistamines are the active enantiomer (levocetirizine) or metabolite (desloratadine & fexofenadine) derivatives of second-generation drugs intended to have increased efficacy with fewer adverse drug reactions. Indeed, fexofenadine is associated with a decreased risk of cardiac arrhythmia compared to terfenadine. However, there is little evidence for any advantage of levocetirizine or desloratadine, compared to cetirizine or loratadine, respectively. In chemistry, enantiomers (from the Greek ἐνάντιος, opposite, and μέρος, part or portion) are stereoisomers that are nonsuperimposable complete mirror images of each other, much as ones left and right hands are the same but opposite. ... A metabolite is the product of metabolism. ... Efficacy is the ability to produce a desired amount of a desired effect. ... An adverse drug reaction (abbreviated ADR) or adverse drug event (abbreviated ADE) is an expression that describes the unwanted, negative consequences associated with the use of given medications. ... Cardiac arrhythmia is any of a group of conditions in which the electrical activity of the heart is irregular or is faster or slower than normal. ... Cetirizine hydrochloride (IPA sɛ.ˈtɪɹ.ɪ.ˌzin) is a major metabolite of hydroxyzine, and a racemic selective H1 receptor antagonist used in the treatment of allergies, hay fever, angioedema, and urticaria. ... Loratadine is a drug used to treat allergies, and marketed for its nonsedating properties. ...


Systemic, second-generation

Acrivastine is a medication used for the treatment of allergies and hay fever. ... Astemizole is a second generation antihistamine that has a long duration of action. ... Cetirizine hydrochloride (IPA sɛ.ˈtɪɹ.ɪ.ˌzin) is a major metabolite of hydroxyzine, and a racemic selective H1 receptor antagonist used in the treatment of allergies, hay fever, angioedema, and urticaria. ... Loratadine is a drug used to treat allergies, and marketed for its nonsedating properties. ... Mizolastine is an antihistamine. ... Terfenadine is an antihistamine formerly used for the treatment of allergic conditions. ...

Topical, second-generation

Azelastine hydrochloride is an antihistamine and mast cell stabilizer available as a nasal spray (Astelin®) for hay fever and as eye drops (Optilar®) for allergic conjunctivitis. ... Levocabastine is a selective second-generation H1-receptor antagonist used for allergic conjunctivitis. ... Olopatadine hydrochloride is an antihistamine and mast cell stabilizer, usually sold as a prescription eye drop (0. ...

Systemic, third-generation

Xyzal Levocetirizine (as levocetirizine dihydrochloride) is a third generation non-sedative antihistamine, developed from the second generation antihistamine cetirizine. ... Desloratadine is a drug used to treat allergies. ... Fexofenadine hydrochloride (brand names include Allegra® and Telfast®) is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms. ...

Common structural features

Structure of these drugs varies from case to case. There are no common structural features.


References

  1. ^ Leurs R, Church MK, Taglialatela M (2002). "H1-antihistamines: inverse agonism, anti-inflammatory actions and cardiac effects". Clin Exp Allergy 32 (4): 489-98. PMID 11972592. 
  2. ^ Simons FE (2004, Nov 18). "Advances in H1-antihistamines". N Engl J Med 351 (21): 2203-17. PMID 15548781 Abstract. 
  3. ^ a b c d e Rossi S (Ed.) (2004). Australian Medicines Handbook 2004. Adelaide: Australian Medicines Handbook. ISBN 0-9578521-4-2
  4. ^ Hoagland, R.J., Deitz, E.N., Myers, P.W., Cosand, H.C., "Antihistaminic drugs for colds: Evaluation Based on a Controlled Study." Journal of the American Medical Association 143(2), pp. 157-160
  5. ^ Fourneau E, Bovet D (1933). Recherches sur l'action sympathicolytique d'un nouveau derive du dioxane. Arch Int Pharmacodyn 46, 178-91.
  6. ^ a b c Nelson, WL (2002). In Williams DA, Lemke TL (Eds.). Foye's Principles of Medicinal Chemistry (5 ed.). Philadelphia: Lippincott Williams & Wilkins. ISBN 0-683-30737-1

The Australian Medicines Handbook or AMH is a medical reference text commonly used in practice by health professionals (particularly general practitioners and pharmacists) in Australia. ...

External links

Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... A histamine antagonist is an agent which serves to inhibit the release or action of histamine. ... A section of the Anatomical Therapeutic Chemical Classification System. ... Ethers can refer to: In internet routing, the term associated with hosts In Organic chemistry, the plural of ether This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Carbinoxamine is an antihistamine. ... Clemastine is an over-the-counter antihistamine sold in the United States under the name Tavist. ... Chlorphenoxamine is an antipruritic. ... Diphenylpyraline is an antihistamine. ... Diphenhydramine hydrochloride (trade name Benadryl as produced by Johnson & Johnson, or Dimedrol outside the U.S. & Canada. ... This article or section may be confusing or unclear for some readers, and should be edited to rectify this. ... Orphenadrine (Norflex®, Disipal®, Banflex®, Flexon® and others) is an anticholinergic and NMDA receptor antagonist [1]drug belonging to the ethanolamine class of antihistamines. ... Phenyltoloxamine is an antihistamine with sedative and analgesic effects. ... Categories: Stub | Antihistamines ... Chlorphenamine (INN) or chlorpheniramine (USAN, former BAN), commonly marketed as its salt chlorphenamine maleate (CPM), is first-generation antihistamine used in the prevention of the symptoms of allergic conditions such as rhinitis and urticaria. ... Dexbrompheniramine maleate is an antihistamine used to treat allergic conditions such as hay fever or urticaria. ... Dexchlorpheniramine maleate (Polaramine®, Schering) is an antihistamine used to treat allergic conditions such as hay fever or urticaria. ... Dimetindene is an antipruritic. ... Pheniramine maleate is an antihistamine used to treat allergic conditions such as hay fever or urticaria. ... Talastine (also known as Aganon and Ahanon) is an antihistamine. ... Ethylene diamine (EDA), or 1,2-diaminoethane, is an organic compound from the amines group. ... Chloropyramine is a classical (old or first generation) antihistamine drug approved in some Eastern European countries for the treatment of allergic conjuctivitis, allergic rhinitis, bronchial asthma, and other atopic (allergic) conditions. ... Histapyrrodine is an antihistamine with anticholinergic properties. ... Mepyramine[1] is a first generation antihistamine. ... Methapyrilene is a pyridine antihistamine. ... Tripelennamine (INN, also known as pyribenzamine) is a first generation pyridine antipruritic and antihistamine in the ethylenediamine class. ... Phenothiazines are the largest of the 5 main classes of antipsychotic drugs. ... Alimemazine (INN), also known as trimeprazine (former BAN and USAN; trade names Nedeltran, Panectyl, Repeltin, Therafene, Theralen, Theralene, Vallergan, Vanectyl, or Temaril), commonly provided as a tartrate salt, is a phenothiazine derivative that is used as an antipruritic (it prevents itching from causes such as eczema or poison ivy, by... Hydroxyethylpromethazine is a promethazine derivative used as an antihistamine. ... Isothipendyl is an antipruritic. ... Mequitazine is an antihistamine. ... Methdilazine is an antihistamine. ... Oxomemazine is an antihistamine. ... Promethazine is a first-generation H1 receptor antagonist antihistamine and antiemetic medication. ... Basic piperazine structure Piperazine is a six-sided organic ring compound containing two opposing nitrogen atoms (see image). ... Buclizine is an antihistamine of the piperazine derivative family. ... Cetirizine hydrochloride (IPA sÉ›.ˈtɪɹ.ɪ.ËŒzin) is a major metabolite of hydroxyzine, and a racemic selective H1 receptor antagonist used in the treatment of allergies, hay fever, angioedema, and urticaria. ... This article belongs in one or more categories. ... Cinnarizine is an anti histaminic drug which is mainly used for the contol of vomiting due to motion sickness. ... Cyclizine is an antihistamine drug used to treat nausea, vomiting and dizziness associated with motion sickness, vertigo and post-operative following administration of general anaesthesia and opioids. ... Hydroxyzine (pronounced ) is a first-generation antihistamine, of the piperazine class that is an H1 receptor antagonist. ... Xyzal Levocetirizine (as levocetirizine dihydrochloride) is a third generation non-sedative antihistamine, developed from the second generation antihistamine cetirizine. ... Meclizine (proposed INN is meclozine) is an antihistamine, considered to be an antiemetic. ... Niaprazine (Nopron) is a piperazine derivative drug which acts as a sedating antihistamine. ... Oxatomide is a piperazine antihistamine. ... Antazoline is an antihistamine used to relieve nasal congestion and in eye drops, usually in combination with naphazoline, to relieve the symptoms of allergic conjunctivitis. ... Azatadine is an antihistamine. ... Bamipine is an antihistamine employed as an antipruritic. ... Cyproheptadine (usually as cyproheptadine hydrochloride, trade name Periactin) is an antihistaminic and antiserotonergic agent. ... Deptropine (INN, also known as dibenzheptropine) is an antihistamine with anticholinergic properties. ... Dimebon (Dimebolin) is an antihistamine drug which has been used clinically in Russia since 1983. ... Ebastin is non sedating H1 antihistamine Does not penetratethe blood brain barrier and thus allow an effective blocked of H1 receptor in peripheral tissue without centeral side effect i. ... Epinastine hydrochloride (Elestat®) is an antihistamine that is used in eye drops to treat allergic conjunctivitis. ... Ketotifen fumarate (Zaditor®) is an H1-antihistamine available in two forms. ... Mebhydroline is an antihistamine. ... Mizolastine is an antihistamine. ... Phenindamine is an antihistamine. ... Pimethixene is an antihistamine often used to treat hyperactivity, anxiety, sleep disorders, and allergy. ... Pyrrobutamine is an antihistamine. ... Rupatadine is a new selective histamine H1 receptor and platelet-activating factor (PAF) antagonist. ... Triprolidine hydrochloride is an over-the-counter antihistamine. ... Acrivastine is a medication used for the treatment of allergies and hay fever. ... Astemizole is a second generation antihistamine that has a long duration of action. ... Azelastine hydrochloride is an antihistamine and mast cell stabilizer available as a nasal spray (Astelin®) for hay fever and as eye drops (Optilar®) for allergic conjunctivitis. ... Desloratadine is a drug used to treat allergies. ... Fexofenadine hydrochloride (brand names include Allegra® and Telfast®) is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms. ... Loratadine is a drug used to treat allergies, and marketed for its nonsedating properties. ... Terfenadine is an antihistamine formerly used for the treatment of allergic conditions. ... In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, nasopharynx, or the eye. ... Bamipine is an antihistamine employed as an antipruritic. ... Chloropyramine is a classical (old or first generation) antihistamine drug approved in some Eastern European countries for the treatment of allergic conjuctivitis, allergic rhinitis, bronchial asthma, and other atopic (allergic) conditions. ... Chlorphenoxamine is an antipruritic. ... Clemastine is an over-the-counter antihistamine sold in the United States under the name Tavist. ... Dimetindene is an antipruritic. ... Diphenhydramine hydrochloride (trade name Benadryl as produced by Johnson & Johnson, or Dimedrol outside the U.S. & Canada. ... Isothipendyl is an antipruritic. ... Mepyramine[1] is a first generation antihistamine. ... Promethazine is a first-generation H1 receptor antagonist antihistamine and antiemetic medication. ... Thenalidine is an antihistamine used as an antipruritic. ... This article or section does not cite its references or sources. ... In physiology, corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. ... Antazoline is an antihistamine used to relieve nasal congestion and in eye drops, usually in combination with naphazoline, to relieve the symptoms of allergic conjunctivitis. ... Azelastine hydrochloride is an antihistamine and mast cell stabilizer available as a nasal spray (Astelin®) for hay fever and as eye drops (Optilar®) for allergic conjunctivitis. ... Emedastine difumarate (Emadine®) is an antihistamine used in eye drops to treat allergic conjunctivitis. ... Epinastine hydrochloride (Elestat®) is an antihistamine that is used in eye drops to treat allergic conjunctivitis. ... Ketotifen fumarate (Zaditor®) is an H1-antihistamine available in two forms. ... Montelukast is a leukotriene receptor antagonist (LTRA) used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies. ... Olopatadine hydrochloride is an antihistamine and mast cell stabilizer, usually sold as a prescription eye drop (0. ... The Anatomical Therapeutic Chemical Classification System is used for the classification of drugs. ... Gut redirects here. ... A section of the Anatomical Therapeutic Chemical Classification System. ... Look up antacid in Wiktionary, the free dictionary. ... An antiemetic is a drug that is effective against vomiting and nausea. ... An H2-receptor antagonist, often shortened to H2-antagonist, is a drug used to block the action of histamine on parietal cells in the stomach, decreasing acid production by these cells. ... Proton pump inhibitors (or PPIs) are a group of drugs whose main action is pronounced and long-lasting reduction of gastric acid production. ... Laxatives (or purgatives) are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. ... An antidiarrhoeal drug is any medication which provides symptomatic relief for diarrhoea. ... For other uses, see Blood (disambiguation). ... A section of the Anatomical Therapeutic Chemical Classification System. ... An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. ... An antiplatelet drug is a member of a class of pharmaceuticals that decreases platelet aggregation and inhibits thrombus formation. ... Thrombolytic drugs are used in medicine to dissolve blood clots in a procedure termed thrombolysis. ... The circulatory system or cardiovascular system is the organ system which circulates blood around the body of most animals. ... A section of the Anatomical Therapeutic Chemical Classification System. ... Antiarrhythmic agents are a group of pharmaceuticals that are used to suppress fast rhythms of the heart (cardiac arrhythmias), such as atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation. ... Antihypertensives are a class of drugs that are used in medicine and pharmacology to treat hypertension (high blood pressure). ... This illustration shows where some types of diuretics act, and what they do. ... A vasodilator is a drug or chemical that relaxes the smooth muscle in blood vessels, which causes them to dilate. ... An antianginal is any drug used in the treatment of angina pectoris, a symptom of ischaemic heart disease. ... Beta blockers or beta-adrenergic blocking agents are a class of drugs used to treat a variety of cardiovascular conditions and some other diseases. ... Captopril, the first ACE inhibitor ACE inhibitors, or inhibitors of Angiotensin-Converting Enzyme, are a group of pharmaceuticals that are used primarily in treatment of hypertension and congestive heart failure, in most cases as the drugs of first choice. ... Hypolipidemic agents, or antihyperlipidemic agents, are a diverse group of pharmaceuticals that are used in the treatment of hyperlipidemias. ... This article is about the organ. ... A section of the Anatomical Therapeutic Chemical Classification System. ... Emollients soften skin (and moisturisers add moisture). ... Antipruritics, also known as anti-itch drugs, are medications that inhibit the itching (Latin: pruritus) that is often associated with sunburns, allergic reactions, eczema, psoriasis, chickenpox, fungal infections, insect bites and stings like those from mosquitoes, fleas, and mites, and contact dermatitis and urticaria caused by plants such as poison... -1... A section of the Anatomical Therapeutic Chemical Classification System. ... Hormonal contraception refers to birth control methods that act on the hormonal system. ... Fertility medication may in a larger sense include any medication that enhances fertility, but in a specific sense consists of agents that stimulate follicle development of the ovary. ... Selective estrogen receptor modulators (SERMs) is a class of medication that acts on the estrogen receptor. ... Sex hormones are hormones that affect the reproductive system. ... The endocrine system is an integrated system of small organs that involve the release of extracellular signaling molecules known as hormones. ... A section of the Anatomical Therapeutic Chemical Classification System. ... An anti-diabetic drug or oral hypoglycemic agent is used to treat diabetes mellitus. ... In physiology, corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. ... Sex hormones are hormones that affect the reproductive system. ... thyroxine (T4) triiodothyronine (T3) Thyroxine, T4 Triiodothyronine, T3 The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are tyrosine-based hormones produced by the thyroid gland. ... An infection is the detrimental colonization of a host organism by a foreign species. ... A section of the Anatomical Therapeutic Chemical Classification System. ... A section of the Anatomical Therapeutic Chemical Classification System. ... Staphylococcus aureus - Antibiotics test plate. ... Antiviral drugs are a class of medication used specifically for treating viral infections. ... A vaccine is an antigenic preparation used to establish immunity to a disease. ... An antifungal drug is medication used to treat fungal infections such as athletes foot, ringworm, candidiasis (thrush), serious systemic infections such as cryptococcal meningitis, and others. ... Antiprotozoal agents (ATC code: ATC P01) is a class of pharmaceuticals used in treatment of protozoal infections. ... Anthelmintics (in the U.S., antihelminthics) are drugs that expel parasitic worms (helminthes) from the body or kill them. ... In medicine, malignant is a clinical term that means to be severe and become progressively worse, as in malignant hypertension. ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ... A section of the Anatomical Therapeutic Chemical Classification System. ... Chemotherapy, in its most general sense, refers to treatment of disease by chemicals that kill cells, specifically those of micro-organisms or cancer. ... Immunostimulators are the drugs which stimulate the immune system by inducing activation or increasing activity of any of its components. ... For a list of immunosuppressive drugs, see the transplant rejection page. ... For other uses of Muscle, see Muscle (disambiguation). ... This article is about the skeletal organs. ... For other uses, see Joint (disambiguation). ... A section of the Anatomical Therapeutic Chemical Classification System. ... Crystal structure of human sex hormone-binding globulin, transporting 5α-dihydrotestosterone. ... Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. ... Disease-modifying antirheumatic drugs is a category of drugs used in many autoimmune diseases to slow down disease progression. ... In physiology, corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. ... A muscle relaxant is a drug which decreases the tone of a muscle. ... For other uses, see Brain (disambiguation). ... The nervous system is a highly specialized network whose principal components are nerves called neurons. ... A section of the Anatomical Therapeutic Chemical Classification System. ... Anesthesia or anaesthesia (see spelling differences) has traditionally meant the condition of having the perception of pain and other sensations blocked. ... An analgesic (colloquially known as a painkiller) is any member of the diverse group of drugs used to relieve pain (achieve analgesia). ... The anticonvulsants, sometimes also called antiepileptics, belong to a diverse group of pharmaceuticals used in prevention of the occurrence of epileptic seizures. ... A mood stabilizer is a psychiatric medication used to treat mood disorders characterized by rapid and unstable mood shifts. ... An anxiolytic is a drug prescribed for the treatment of symptoms of anxiety. ... The term antipsychotic is applied to a group of drugs used to treat psychosis. ... Prozac, a selective serotonin reuptake inhibitor (SSRI) Serotonin-norepinephrine reuptake inhibitor, Venlafaxine An antidepressant is a psychiatric medication or other substance (nutrient or herb) used for alleviating depression or dysthymia (milder depression). ... Sustained-Release 15mg Dexedrine Spansules. ... A sedative is a substance that depresses the central nervous system (CNS), resulting in calmness, relaxation, reduction of anxiety, sleepiness, and slowed breathing, as well as slurred speech, staggering gait, poor judgment, and slow, uncertain reflexes. ... Among quadrupeds, the respiratory system generally includes tubes, such as the bronchi, used to carry air to the lungs, where gas exchange takes place. ... A section of the Anatomical Therapeutic Chemical Classification System. ... A bronchodilator is a medication intended to improve bronchial airflow. ... A decongestant is a broad class of drugs designed to symptomatically treat ailments affecting the respiratory system. ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ... Agonists In pharmacology an agonist is a substance that binds to a specific receptor and triggers a response in the cell. ... Antagonists will block the binding of an agonist at a receptor molecule, inhibiting the signal produced by a receptor-agonist coupling. ... A neurotransmitter uptake inhibitor is a drug which inhibits the reuptake of the neurotransmitter, thus extending the duration of its effect. ... A biogenic amine is a biogenic substance with an amine group. ... Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group that is connected to an aromatic ring by a two-carbon chain (-CH2-CH2-). All monoamines are derived from aromatic amino acids like phenylalanine, tyrosine, histidine, tryptophan, and the thyroid hormones by the action of aromatic amino acid decarboxylase... In the field of neurochemistry, 5-HT receptors are receptors for the neurotransmitter and peripheral signal mediator serotonin, also known as 5-hydroxytryptamine or 5-HT. 5-HT receptors are located on the cell membrane of nerve cells and other cell types in animals and mediate the effects of serotonin... A serotonin receptor agonist is a compound that activates serotonin receptors, mimicking the effect of the neurotransmitter serotonin. ... A serotonin antagonist acts to inhibit the action at serotonin receptors. ... Skeletal formula of ondansetron, the prototypical 5-HT3 antagonist The 5-HT3 antagonists are a class of medications which act as receptor antagonists at the 5-hydroxytryptamine-3 receptor (5-HT3 receptor), a subtype of serotonin receptor found in terminals of the vagus nerve and certain areas of the brain. ... A serotonin uptake inhibitor is a drug which acts as a neurotransmitter uptake inhibitor on serotonin receptors. ... SSRI redirects here; for other uses, see SSRI (disambiguation). ... The dopamine receptors are a class of metabotropic G-protein-coupled receptors with the neurotransmitter dopamine as their endogenous ligand. ... Dopamine agonist is a synthetic drug that mimics the effect of the neurotransmitter dopamine. ... A dopamine antagonist is a drug which blocks dopamine receptors (of which there are five types in the human body; they are found in the brain, peripheral nervous system, blood vessels, and the kidney). ... Dopamine Dopamine Reuptake Inhibitors (DARI), Dopamine Uptake Inhibitors, Dopamine Transporter Inhibitors are compounds that inhibit the reuptake of extracellular dopamine back into the presynaptic cell by blocking the cell membrane-spanning dopamine transporter. ... Epinephrine Norepinephrine The adrenergic receptors (or adrenoceptors) are a class of G protein-coupled receptors that are targets of the catecholamines. ... An adrenergic is a drug, or other substance, which has effects similar to, or the same as, epinephrine (adrenaline). ... An Adrenergic antagonist is a pharmaceutical substance that acts to inhibit the action of the adrenergic receptors. ... Alpha blockers (also called alpha-adrenergic blocking agents) constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles. ... Beta blockers or beta-adrenergic blocking agents are a class of drugs used to treat a variety of cardiovascular conditions and some other diseases. ... A adrenergic uptake inhibitor is a drug which blocks the reuptake of adrenergic neurotransmitters. ... The histamine receptors are a class of G-protein coupled receptors with histamine as their endogenous ligand. ... A histamine agonist is a drug which causes increased activity at the histamine receptor. ... A histamine antagonist is an agent which serves to inhibit the release or action of histamine. ... An H2-receptor antagonist, often shortened to H2-antagonist, is a drug used to block the action of histamine on parietal cells in the stomach, decreasing acid production by these cells. ... An acetylcholine receptor (abbreviated AChR) is an integral membrane protein that responds to the binding of the neurotransmitter acetylcholine. ... A synapse is cholinergic if it uses acetylcholine as its neurotransmitter. ... A muscarinic receptor agonist is an agent that enhances the activity of the muscarinic acetylcholine receptor. ... A nicotinic agonist is a drug which enhances the action at the nicotinic acetylcholine receptor. ... An anticholinergic agent is a member of a class of pharmaceutical compounds which serve to reduce the effects mediated by acetylcholine in the central nervous system and peripheral nervous system. ... A muscarinic receptor antagonist is an agent that reduces the activity of the muscarinic acetylcholine receptor. ... A nicotinic antagonist is a type of anticholinergic which inhibits the action at nicotinic acetylcholine receptors. ... A cholinesterase inhibitor or anticholinesterase is a chemical that inhibits a cholinesterase enzyme from breaking down acetylcholine, so increasing both the level and duration of action of the neurotransmitter acetylcholine. ... This article is about the class of chemicals. ... The GABA receptors are a group of receptors with γ-aminobutyric acid (GABA) as their endogenous ligand. ... A GABA agonist is a drug which acts to stimulate or increase the action at the GABA receptor. ... GABA antagonists are drugs which inhibit the action of GABA. Examples include Bicuculline and Metrazol. ... Glutamate is a neurotransmitter in nerve cells which binds to all glutamate receptors located on neuron membranes, and is an example of a transmembrane receptor. ... The NMDA receptor (NMDAR) is an ionotropic receptor for glutamate (NMDA (N-methyl d-aspartate) is a name of its selective specific agonist). ... NMDA receptor antagonists are a class of anesthetics that work to antagonize, or inhibit the action of, the NMDA receptor (NMDAR). ...

 
 

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