Drugs online research references
Clin Exp Allergy. 1999 Jul;29 Suppl 3:190-6.
Electrophysiological effects of cetirizine, astemizole and D-sotalol in a canine model of long QT syndrome.
Weissenburger J, Noyer M, Cheymol G, Jaillon P.
Pharmacology Laboratory, Faculte de Medecine St Antoine, Universite Pierre et Marie Curie, Paris, France.
Observations of torsades de pointes during therapy with terfenadine and astemizole has raised concern about the cardiac safety of non-sedating H1-antagonist agents. We compared cetirizine, another compound of that class, to D-sotalol and to astemizole in a model of acquired long QT syndrome. Open-chest surgery was performed in adult beagle dogs anaesthetized with halothane and thiopental. Bradycardia was produced with beta-adrenergic blockade and sinus node crush. Four left ventricular intramyocardial unipolar monophasic action potentials (MAP) were recorded during atrial pacing at basic cycle lengths (BCL) 400-1500 msec, before and during three successive 1-h drug infusions (0.14, 0.45 and 1.4 mg/kg/h for astemizole and cetirizine and 1.1, 2.2 and 4.5 mg/kg/h for D-sotalol). Dose- and bradycardia-dependent prolongations of MAP duration (MAPD) were produced by D-sotalol (P < 0.001) and astemizole (P < 0.001) but not by cetirizine. At BCL 1500 ms, the three infusions of astemizole prolonged endocardial MAPD from 323 +/- 8 msec (mean +/- SE) at baseline to 343 +/- 10, 379 +/- 13 and 468 +/- 26 msec, respectively (n = 9). Sotalol prolonged that MAPD from 339 +/- 6 msec to 377 +/- 7, 444 +/- 15 and 485 +/- 24 msec (n = 7). In contrast, cetirizine did not prolong MAPD: 341 +/- 8 msec at baseline Vs 330 +/- 8, 324 +/- 9 and 323 +/- 11 msec (n = 9). Drug-induced increase in transmural dispersion reached +79 +/- 19 msec after astemizole, +59 +/- 21 msec after D-sotalol and only +7 +/- 11 msec after cetirizine. Runs of ventricular tachycardias and torsades de pointes occurred during dose three of astemizole (5/9 dogs) and D-sotalol (4/7 dogs) but never during cetirizine. In the present model, astemizole and D-sotalol but not cetirizine prolonged MAPD and transmural dispersions of repolarization and produced torsades de pointes. These results suggest that the halothane-anaesthetized bradycardic dog could be a valuable model to discriminate drugs for their class III effects and proarrhythmic potencies.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10444236&dopt=Abstract
word match zyrtec online literature
Pneumonol Alergol Pol. 1992;60(11-12):22-7.
[Effect of cetirizine, selective H1 antagonist of histamine on skin and bronchial reactivity and cellular histamine release in allergic diseases]
[Article in Polish]
Siergiejko Z, Michalska I, Rogalewska A, Chyrek-Borowska S.
Kliniki Alergologii AM, Bialymstoku.
The study aimed at evaluating an effect of cetirizine--selective antagonist of histamine H1 receptor--on skin and bronchial reaction to histamine, and histamine release from the cells by pollen antigen and anti-IgE. Skin reactivity was tested thrice in 33 patients treated with Zyrtec (Polfa) for the chronic urticaria or allergic rhinitis. Reaction of the bronchi to histamine was tested with a technique described by Ryan et al in 10 asthmatic patients. As effect of cetirizine on histamine release from neutrophils was evaluated in patients with pollinosis before and on the fourth day of therapy. It was shown that the treatment with Zyrtec markedly decreases skin reaction to histamine. Single dose of drug administered 4 hours before the tests markedly restricts reactivity of the bronchi. Daily dose of 10 mg administered to patients with pollinosis stabilizes membranes of neutrophils.
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word match zyrtec online literature
Ann Allergy. 1992 Mar;68(3):251-4.
Cetirizine does not influence the immune response.
Canonica GW, Pesce G, Ruffoni S, Buscaglia S, Boero F, Jing G, Rihoux JP, Ciprandi G.
Allergy and Clinical Immunology Service, Department of Internal Medicine Genoa, Italy.
Antihistamines are frequently employed in the treatment of allergic rhinitis and urticaria-angioedema syndrome. We analyzed the in vitro effects of cetirizine on the immune response. To this end the proliferation of peripheral mononuclear cells induced by mitogen and by -CD3, -CD2, or -CD28 monoclonal antibodies has been studied. Since the plasma peak of cetirizine following ingestion of 10 mg is about 1 microgram/mL, the drug was tested in the cultures at the concentration of 0.1, 1, or 10 micrograms/mL. No influence of cetirizine on T cell proliferation was detected. We also evaluated the effect of cetirizine on the expression of the following markers expressed by T cells upon activation: lymphocyte markers ICAM-1, HLA-DR, and CD25 surface expression, alpha-1-acid glycoprotein has been also studied. There was no effect of cetirizine on the investigated immunologic parameters; these data acquire clinical relevance when related to previous reports showing a depression of the immunologic response exerted by other compounds such as ketotifen and theophylline and when related to the recent data about the modulation of ICAM-1 expression on eosinophils by cetirizine. Cetirizine does not affect ICAM-1 expression of lymphocyte membrane.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1347675&dopt=Abstract
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