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 histamine receptors are termed antihistamines; other agents may have antihistaminergic action but are not true antihistamines.[citation needed]
In common use, the term "antihistamine" refers only to H1-antihistamines. Virtually all H1-antihistamines function as inverse agonists at the histamine H1-receptor, as opposed to neutral antagonists, as was previously believed.[1][2][3]
^Leurs R, Church MK, Taglialatela M (April 2002). "H1-antihistamines: inverse agonism, anti-inflammatory actions and cardiac effects". Clinical and Experimental Allergy. 32 (4): 489–98. doi:10.1046/j.0954-7894.2002.01314.x. PMID 11972592. S2CID 11849647.
^Cite error: The named reference :1 was invoked but never defined (see the help page).
^Khilnani G, Khilnani AK (September 2011). "Inverse agonism and its therapeutic significance". Indian Journal of Pharmacology. 43 (5): 492–501. doi:10.4103/0253-7613.84947. PMC 3195115. PMID 22021988.
H1antagonists, also called H1 blockers, are a class of medications that block the action of histamine at the H1 receptor, helping to relieve allergic...
antihistamines are inverse agonists at the H1 receptor, but it was previously thought that they were antagonists. Clinically, H1-antihistamines are used to treat...
"antihistamine" typically refers to H1 antagonists, which relieve allergic reactions. Like the H1antagonists, some H2 antagonists function as inverse agonists...
An H3 receptor antagonist is a type of antihistaminic drug used to block the action of histamine at H3 receptors. Unlike the H1 and H2 receptors which...
antipsychotics, which are purely dopamine antagonists). They include, but are not limited to: Cyproheptadine blocks 5-HT2A, H1 and is a mild anticholinergic. Methysergide...
inverse agonists or neutral antagonists, they are more properly described as H1-antihistamines rather than H1-receptor antagonists.15 Cará AM, Lopes-Martins...
(2013). "Review of the histamine system and the clinical effects of H1antagonists: basis for a new model for understanding the effects of insomnia medications"...
classified as antagonists of histamine H1 receptors have been reclassified as inverse agonists. Many antagonists are reversible antagonists that, like most...
and stimulation of sensory nerve endings (causing itching and pain). H1antagonists, commonly known as antihistamines, are used to alleviate symptoms of...
Clemizole is an H1antagonist. Benzimidazoles substituted with an alkylamine at position 2 have a venerable history as H1 antihistaminic agents. The standard...
(January 1984). "The pharmacokinetics and antihistaminic of the H1 receptor antagonist hydroxyzine". The Journal of Allergy and Clinical Immunology. 73...
Mequitazine (trade name Primalan) is an H1antagonist and anticholinergic of the phenothiazine chemical class. It is used to treat allergies and rhinitis...
Clemastine, also known as meclastin, is a first-generation H1 histamine antagonist (antihistamine) with anticholinergic properties (drying) and sedative...
an inverse agonist of the histamine H1 receptor—and to a lesser extent an anticholinergic—specifically an antagonist of the muscarinic acetylcholine receptors...
acts primarily as a strong antagonist of the H1 receptor (antihistamine, Ki = 1.4 nM) and a moderate mACh receptor antagonist (anticholinergic), and also...
A dopamine antagonist, also known as an anti-dopaminergic and a dopamine receptor antagonist (DRA), is a type of drug which blocks dopamine receptors...
used when administering meclizine to the elderly. Meclizine is an antagonist at H1 receptors. It possesses anticholinergic, central nervous system depressant...
4–6 hours. It is a first-generation antihistamine and works by blocking the H1 receptor. Common side effects include sleepiness, restlessness, and weakness...
Isothipendyl is a 1st generation H1antagonist (antihistamine) and anticholinergic used as an antipruritic. In the 2020s, at least, it is rarely used...
Chloropyramine is known as a competitive reversible H1 receptor antagonist (also known as an H1 inverse agonist), meaning that it exerts its pharmacological...
Bisulepin is strong and relatively selective antihistamine (H1antagonist) with hypnotic, antiadrenergic and very weak anticholinergic and antiserotonergic...
known as α-blockers or α-adrenoreceptor antagonists, are a class of pharmacological agents that act as antagonists on α-adrenergic receptors (α-adrenoceptors)...
rebound hives once discontinued. H2-receptor antagonists are sometimes used in addition to H1-antagonists to treat urticaria, but there is limited evidence...
allergic conjunctivitis. Carbinoxamine is a histamine antagonist, specifically an H1-antagonist. The maleic acid salt of the levorotatory isomer is sold...
toxicity in overdose. As an H1 receptor antagonist, mirtazapine is extremely potent, and is in fact one of the most potent H1 receptor inverse agonists...
the H1 receptor (and not H2, etc.). Clinically, H1antagonists are used to treat certain allergies. Sedation is a common side-effect, and some H1 antagonists...
These may need to be given as a combination of H1antagonists, or possibly with an H2-receptor antagonist such as cimetidine. Over-the-counter vitamin C...
cetirizine. Cetirizine acts as a highly selective antagonist of the histamine H1 receptor. The Ki values for the H1 receptor are approximately 6 nM for cetirizine...
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