Hj antihistamine

Hj Antihistamine Treatment in Allergic Diseases. H -receptor antagonists are used for the symptomatic treatment of several allergic... 

Nielsen L. Johnsen CR, Mosbech H, Poulsen LK. Mailing HJ Antihistamine premedication in specific cluster immunotherapy a double-blind, placebo-controlled study J Allergy Clin Immunol 1996 97 1207-1213. 

Epinephrine autoinjectors should be prescribed in the context of a written Anaphylaxis Emergency Action Plan that is developed with the input of the person at risk for anaphylaxis, or the caregiver(s) of the child at risk [45]. The Plan should remind the person at risk about the common symptoms and signs of anaphylaxis, stress the importance of prompt epinephrine injection, and clearly state that Hj-antihistamines... 

Hj antihistamines are the most commonly prescribed medications for AR. Hj antihistamines bind to and stabilize the Hj histamine receptor, thereby inhibiting mast cell and basophil mediator release and resulting in reduction of sneezing, itching, rhinorrhea, and ocular irritation. Antihistamines do not prevent histamine release, nor do they bind to already-released histamine. For this reason, maintenance therapy is considered optimal. However, antihistamines are also effective when taken on an as-needed basis.4,11,12 Antihistamines only minimally... 

Histamine regulates granulocyte accumulation to tissues in distinct ways. Allergen-induced accumulation of eosinophils in the skin, nose and airways is potently inhibited by Hj antihistamines [34]. The effect of histamine on eosinophil migration may differ according to the dose. Whereas high doses inhibit eosinophil chemotaxis via... 

Leurs R, Church MK, Taglialatela M Hj-antihistamines inverse agonism, anti-inflammatory actions and cardiac effects. Clin Exp Allergy 2002 32 489-498. 

Antagonists. Most of the so-called Hi-antihistamines also block other receptors, including M-cholinoceptors and D-receptors. Hi-antihistamines are used for the symptomatic relief of allergies (e.g., bamipine, chlorpheniramine, clemastine, dimethindene, mebhydroline pheniramine) as antiemetics (meclizine, dimenhydrinate, p. 330), as over-the-counter hypnotics (e.g., diphenhydramine, p. 222). Promethazine represents the transition to the neuroleptic phenothiazines (p. 236). Unwanted effects of most Hi-antihistamines are lassitude (impaired driving skills) and atropine-like reactions (e.g., dry mouth, constipation). At the usual therapeutic doses, astemizole, cetrizine, fexofenadine, and loratidine are practically devoid of sedative and anticholinergic effects. Hj-antihistamines (cimetidine, ranitidine, famotidine, nizatidine) inhibit gastric acid secretion, and thus are useful in the treatment of peptic ulcers. 

Hj antihistamines are clinically used in the treatment of histamine-mediated allergic conditions. Specifically, these indications may include allergic rhinitis, allergic conjunctivitis, allergic dermatological conditions (contact dermatitis), pruritus (atopic dermatitis, insect... 

First-generation FIj antihistamines are the oldest antihistaminergic drugs and are relatively inexpensive and widely available. Representatives of first-generation Hj antihistamines are ... 

Ethanolamines—(diphenhydramine was the prototypical agent in this group). Ethylenediamines, which were the first group of clinically effective Hj antihistamines developed, (pyrilamine). 

The most common Hj antihistamine drugs are structurally similar to histamine with a substituted ethylamine side chain however, they have two aromatic rings and can be formally represented by the general formula ... 

Traditional or Hj antihistamine drugs block many effects caused by histamine however, it turns out that they are not able to withstand events mediated by H2 receptors, in particular excess gastric juice secretion. In 1977 an H2-receptor antagonist, cimetidine, was proposed, which revolutionized stomach ulcer treatment. Later on, ranitidine was proposed, followed by drugs with minor structural and pharmacological differences such as famotidine and nizatidine. 

Knowledge of the physiological role of histamine in the CNS and evidence for the existence of discrete neuronal networks that could be called histaminergic are still evolving. Histamine-mediated hypothermia, emesis, and hypertension have been shown to exist, and the well-known sedative effects of Hj antihistamines are centrally mediated. 

ANS They have varying degree of a adrenergic blocking activity. They also have weak anti-cholinergic, Hj-antihistaminic and anti 5-HT actions as well. 

Blockade of histamine receptors. Allergic reactions are predominantly mediated by H, receptors. Hj-antihistaminics (p. 118) are mostly used orally. Their therapeutic effect is often disappointing. Indications allergic rhinitis (hay fever). 

Desager JP, Horsmans Y Pharmacokinetic-pharmacodynamic relationships of Hj antihistamines. CUn Pharmacokinet 1995 5 419-432. 

Gonzalez MA, Estes KS. Pharmacokinetic overview of oral second generation Hj antihistamines. J CUn Pharmacol Ther 1998 36 292-300. 

In some individuals, urticarial weals are provoked by physical stimuli, e.g. friction (dermographism), heat or cold. Exercise may induce weals, particularly on the upper trunk (cholinergic urticaria). Physical urticarias may require combined Hj- and receptor receptor antagonists fully to block the vascular effects of histamine, which causes flushing and hypotension. Cyproheptadine is usually the preferred choice of Hj-antihistamine but causes drowsiness. 

Pizotifen and cyproheptadinehlockseTotomn (5-HT) receptors as weU as having some Hj-antihistamine action they can be effective. 

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