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H 1-receptor antagonists are competitive inhibitor of histamine receptor H 1 and are used to treat allergies. This group is often referred simply as antihistamines . Wikimedia Commons has media related to H1 receptor antagonists .
H 1 antagonists, also called H 1 blockers, are a class of medications that block the action of histamine at the H 1 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 ...
Histaminergic means "working on the histamine system", and histaminic means "related to histamine". [1] A histaminergic agent (or drug) is a chemical which functions to directly modulate the histamine system in the body or brain. Examples include histamine receptor agonists and histamine receptor antagonists (or antihistamines).
Cetirizine acts as a highly selective antagonist of the histamine H 1 receptor. [3] The K i values for the H 1 receptor are approximately 6 nM for cetirizine, 3 nM for levocetirizine, and 100 nM for dextrocetirizine, indicating that the levorotatory enantiomer is the main active form. [3]
Alcaftadine, sold under the brand name Lastacaft, is an antihistamine used to help prevent itching of the eyes. [1] It is an H1 histamine receptor antagonist. [1] It is given as an drops in the eye. [1] It was approved for medical use in the United States in July 2010. [3] It is available as a generic medication and as an over-the-counter ...
Rupatadine is a second generation, non-sedating, long-acting histamine antagonist with selective peripheral H 1 receptor antagonist activity. It further blocks the receptors of the platelet-activating factor (PAF) according to in vitro and in vivo studies.
Histamine H 1 receptors are activated by endogenous histamine, which is released by neurons that have their cell bodies in the tuberomammillary nucleus of the hypothalamus. The histaminergic neurons of the tuberomammillary nucleus become active during the 'wake' cycle, firing at approximately 2 Hz; during slow wave sleep , this firing rate ...
Quifenadine is a derivative of quinuclidylcarbinol, which reduces the effects of histamine on organs and systems. Quifenadine is a competitive blocker of H1 receptors. In addition, it activates the diamine oxidase enzyme, which breaks down about 30% of endogenous histamine.