An antihistamine is a drug which serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions, through action at the histamine receptor. Only 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.
In common use, the term antihistamine refers only to H1-receptor antagonists, also known as H1-antihistamines. It has been discovered that these H1-antihistamines are actually inverse agonists at the histamine H1-receptor, rather than antagonists per se. (Leurs, Church & Taglialatela, 2002)
Pharmacology
In allergic reactions an
allergen (a type of
antigen) interacts with and cross-links surface IgE
antibodies on
mast cells and
basophils. 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. Once released, histamine can react with local or widespread tissues through
histamine receptors.
More on
[ Antihistamine ]
Allergy Treatments
Antihistamines - Twitter SearchDear Antihistamines, You're so gentle. Lovingly, Laurenmessengerhatta (El Cho) Sat, 28 Nov 2009 03:26:08 -0000
Dear Antihistamines, You're so gentle. Lovingly, Lauren
@quackadoodle Ya, there are quite a few antihistamines that are used for other things.kittynurse (Martha) Sat, 28 Nov 2009 00:16:23 -0000
@quackadoodle Ya, there are quite a few antihistamines that are used for other things.
@ModelMandyLynn Yeah...I've been taking zinc, Emergen-C, decongestants, and antihistamines with tons of water. Hope you feel better soon.JPruett803 (JPruett803) Fri, 27 Nov 2009 22:31:06 -0000
@ModelMandyLynn Yeah...I've been taking zinc, Emergen-C, decongestants, and antihistamines with tons of water. Hope you feel better soon.
@soopertrev Diabetes/ reaction to antihistamines/ other drugs/ or turkey tryptophan/ general drowsiness...SarahWW (Sarah Wells) Fri, 27 Nov 2009 20:09:28 -0000
@soopertrev Diabetes/ reaction to antihistamines/ other drugs/ or turkey tryptophan/ general drowsiness...
@believenjesus the only thing 2do is control the symptoms & the otc antihistamines dont always work which sucks.fool_that_iam (Chrissy) Fri, 27 Nov 2009 17:01:51 -0000
@believenjesus the only thing 2do is control the symptoms & the otc antihistamines dont always work which sucks.
Up at 2 am enjoying my annual sinus infection. Ran to Walgreens awhile ago for candy & antihistamines.DameJeffrey (Jeffrey R) Fri, 27 Nov 2009 07:57:57 -0000
Up at 2 am enjoying my annual sinus infection. Ran to Walgreens awhile ago for candy & antihistamines.
Subscribe to Antihistamines RSS feed 
Antihistamines - A brief overview of this group of medicines which help with the symptoms of allergies.
Antihistamines: Are Newer Drugs Always a Better Choice? - Medscape review of the properties and uses of these medications, including discussion of research on sedative side effects, and advice for medical professionals on how to use these drugs in treating allergic patients. [Requires free registration]
Prescription Antihistamine Database - Information about medications available by prescription in the U.S., arranged by drug name.
Meta Description: [ Pharmaceutical News; reliable drug information for patients and pharmaceutical marketing professionals; Pharmaceutical Sales - free Advice on how to land job ]