Antihistamine: Difference between revisions

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[[File:Histamine.svg|200px|thumbnail|The structure of ~~Histamine~~]]

[[File:Histamine.svg|200px|thumbnail|The chemical structure of histamine]]

'''Antihistamines''' are ~~pharmaceutical drugs~~ that ~~inhibits~~ the action of [[histamine]] ~~by either blocking its attachment~~ to ~~histamine~~ [[~~receptor~~]]~~s or inhibiting the enzymatic activity of histidine decarboxylase which catalyzes the transformation of [[histidine]] into histamine~~. ~~Anti-histamines are commonly used for the relief of allergies~~<ref>Sicherer, Scott H. M.D., Understanding and Managing Your Child's Food Allergy. Baltimore: The Johns Hopkins University Press, 2006 ISBN 0-8018-8492-6.</ref> and ~~sometimes for their~~ [[~~subjective effects index|psychoactive effects~~]].

'''Antihistamines''' are a class of substances that inhibit the action of [[histamine]]. Antihistamines are commonly used to relieve allergies and to [[sedation|promote sleep]].<ref>Sicherer, Scott H. M.D., Understanding and Managing Your Child's Food Allergy. Baltimore: The Johns Hopkins University Press, 2006 ISBN 0-8018-8492-6.</ref> Recreationally, very high doses can be used to induce [[delirium]] and achieve a [[hallucinogenic]] effect in which the user sees and hears fully-formed, extremely convincing hallucinations. However, this experience is typically considered highly unpleasant by most users.

The toxicity of recreational antihistamine use is poorly understood, although abuse is associated with cognitive deficits.

==Pharmacology==

Most antihistamines ~~have~~ [[Agonist#Agonists|inverse ~~agonistic~~]] ~~effects upon~~ histamine receptors.

Most antihistamines act as [[Agonist#Agonists|inverse agonists]] on histamine [[receptors]], meaning they inhibit the action of histamine by preventing it from binding to them. They may also inhibit the enzymatic activity of histidine decarboxylase which catalyzes the transformation of [[histidine]] into histamine.{{citation needed}}

==Examples==

Antihistamines are ~~seen~~ throughout organic chemistry ~~including~~ psychoactive and anti-allergenic compounds.

Antihistamines are found throughout organic chemistry and include psychoactive and anti-allergenic compounds.

*[[Cyclizine]]

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 {{stub}}
-[[File:Histamine.svg|200px|thumbnail|The structure of Histamine]]
+[[File:Histamine.svg|200px|thumbnail|The chemical structure of histamine]]
-'''Antihistamines''' are pharmaceutical drugs that inhibits the action of [[histamine]] by either blocking its attachment to histamine [[receptor]]s or inhibiting the enzymatic activity of histidine decarboxylase which catalyzes the transformation of [[histidine]] into histamine. Anti-histamines are commonly used for the relief of allergies<ref>Sicherer, Scott H. M.D., Understanding and Managing Your Child's Food Allergy. Baltimore: The Johns Hopkins University Press, 2006 ISBN 0-8018-8492-6.</ref> and sometimes for their [[subjective effects index|psychoactive effects]].
+'''Antihistamines''' are a class of substances that inhibit the action of [[histamine]]. Antihistamines are commonly used to relieve allergies and to [[sedation|promote sleep]].<ref>Sicherer, Scott H. M.D., Understanding and Managing Your Child's Food Allergy. Baltimore: The Johns Hopkins University Press, 2006 ISBN 0-8018-8492-6.</ref> Recreationally, very high doses can be used to induce [[delirium]] and achieve a [[hallucinogenic]] effect in which the user sees and hears fully-formed, extremely convincing hallucinations. However, this experience is typically considered highly unpleasant by most users.
+The toxicity of recreational antihistamine use is poorly understood, although abuse is associated with cognitive deficits.
 ==Pharmacology==
 {{pharmacology}}
-Most antihistamines have [[Agonist#Agonists|inverse agonistic]] effects upon histamine receptors.
+Most antihistamines act as [[Agonist#Agonists|inverse agonists]] on histamine [[receptors]], meaning they inhibit the action of histamine by preventing it from binding to them. They may also inhibit the enzymatic activity of histidine decarboxylase which catalyzes the transformation of [[histidine]] into histamine.{{citation needed}}
 ==Examples==
-Antihistamines are seen throughout organic chemistry including psychoactive and anti-allergenic compounds.
+Antihistamines are found throughout organic chemistry and include psychoactive and anti-allergenic compounds.
 *[[Cyclizine]]