- Mequitazine (trade name Primalan) is an H1 antagonist and anticholinergic of the phenothiazine chemical class. (wikipedia.org)
- They are effective in the relief of allergic symptoms, but are typically moderately to highly-potent muscarinic acetylcholine receptor -antagonists ( anticholinergic ) agents as well. (wikidoc.org)
- 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. (wikidoc.org)
- Once released, histamine can react with local or widespread tissues through histamine receptors . (wikidoc.org)
- The newer second-generation H 1 -antihistamines are far more selective for peripheral histamine H 1 -receptors and have a far improved tolerability profile compared to the first-generation agents. (wikidoc.org)
- Astemizole may also act on histamine H3 receptors, thereby producing adverse effects. (wikidoc.org)
- Alcaftadine is an antagonist at three of the histamine receptors (1, 2 and 4). (mdwiki.org)
- This effect on histamine receptors seems to show lower rates of itching, eosinophil recruitment and redness after exposure to an allergen. (mdwiki.org)
- An H 1 antagonist is a histamine antagonist of the H 1 receptor that serves to reduce or eliminate effects mediated by histamine , an endogenous chemical mediator released during allergic reactions . (wikidoc.org)
- In common use, the term "antihistamine" refers only to H 1 antagonists, also known as H 1 -receptor antagonists and H 1 -antihistamines. (wikidoc.org)
- It has been discovered that these H 1 -antihistamines are actually inverse agonists at the histamine H 1 -receptor, rather than antagonists per se . (wikidoc.org)
- Astemizole is an histamine H1-receptor antagonist. (wikidoc.org)
- Astemizole competitively binds to histamine H1-receptor sites in the gastrointestinal tract, uterus, blood vessels, and bronchial muscle. (wikidoc.org)
- Astemizole does not cross the blood-brain barrier , and H1 receptor binding is mostly in the peripheral rather than central nervous system (CNS depression is thus minimal). (wikidoc.org)
- [4] It is a H 1 histamine receptor blocker . (mdwiki.org)
- Efficacy of mequitazine (Primalan) on the relief of symptoms of allergic rhinoconjunctivitis in children. (wikipedia.org)
- H 1 -antihistamines are clinically used in the treatment of histamine-mediated allergic conditions. (wikidoc.org)
- [3] It is classified as a second-generation antihistamine and works as a selective H1-blocker . (mdwiki.org)
- 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. (wikidoc.org)