Antihistamines | Histamine receptor agonist and antagonist | Medi tutorials

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Written by, Fojla Rahman Zia

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Antihistamines:

Histamines is a mediator of inflammation and stimulant of gastric acid secretion.Antihistamines are those drugs which block the histamin receptor and gives antihistaminergic effect....

H1 receptor agonist:
        2-methyl histamin
        2-pyridyl ethyl amine
H2 receptor agonist:
        4,5 methyl histamine
        impromide
H3 receptor agonist:
        alpha-methyl histamine


Now, H1 receptor antagonist:
   1st generation----
* Potent and powerful sedative:
         Diphenhydramine
         Dimenhydrinate
         Promethazine
         Hydroxyzine
         Doxylamine
* Potent but less sedative:
         Chlorpheniramine
         Chlorcyclizine
* Potent but less sedative:
          pheniramine
          phenindamine
     


   2nd generation----
          acrivastine
          cetrizine, levocetrizine
          loratadine, desloratadine
          fexofenadine

H2 receptor antagonist:
          Renitidine
          Femotidine
          Nizatidine
          Zolentidine


what are the difference between 1st generation and 2nd generation antihistamine?

1st generation antihistamine are more sedative, more lipid soluable, short duration of action and should not given student, driver, working person...

But 2nd generation antihistamine are less sedative, less lipid soluable,long duration of action and should given student, driver, working person...

       

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 Pharmacology