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allergy medication |
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allergy medication DESCRIPTION Zafirlukast is a synthetic, selective peptide leukotriene receptor antagonist(LTRA), with the chemical name 4-(5-cyclopentyloxy-carbonylamino-1-methyl-indol-3-ylmethyl)-3-methoxy-N-o-tolylsulfonylbenzamide allergy medication. The molecular weight of zafirlukast is 575.7 and the structural formula is:
Zafirlukast, a fine white to pale yellow amorphous powder, is practically insolublein water allergy medication. It is slightly soluble in methanol and freely soluble in tetrahydrofuran,dimethylsulfoxide, and acetone allergy medication. ACCOLATE is supplied as 10 and 20 mg tablets for oral administration allergy medication. Inactive Ingredients: Film-coated tablets containing croscarmellose sodium,lactose, magnesium stearate, microcrystalline cellulose, povidone, hypromellose,and titanium dioxide allergy medication.
In vitro studies demonstrated that zafirlukast antagonized the contractileactivity of three leukotrienes (LTC 4 , LTD 4 and LTE 4 ) in conducting airwaysmooth muscle from laboratory animals and humans allergy medication. Zafirlukast prevented intradermalLTD 4 -induced increases in cutaneous vascular permeability and inhibited inhaledLTD 4 -induced influx of eosinophils into animal lungs allergy medication. Inhalational challengestudies in sensitized sheep showed that zafirlukast suppressed the airway responsesto antigen; this included both the early- and late-phase response and the nonspecifichyperresponsiveness allergy medication. In humans, zafirlukast inhibited bronchoconstriction caused by several kindsof inhalational challenges allergy medication. Pretreatment with single oral doses of zafirlukastinhibited the bronchoconstriction caused by sulfur dioxide and cold air in patientswith asthma allergy medication. Pretreatment with single doses of zafirlukast attenuated the early-and late-phase reaction caused by inhalation of various antigens such as grass,cat dander, ragweed, and mixed antigens in patients with asthma allergy medication. Zafirlukastalso attenuated the increase in bronchial hyperresponsiveness to inhaled histaminethat followed inhaled allergen challenge allergy medication. Clinical Pharmacokinetics and Bioavailability: Distribution Metabolism Excretion In the pivotal bioequivalence study, the mean terminal half-life of zafirlukastis approximately 10 hours in both normal adult subjects and patients with asthma allergy medication. In other studies, the mean plasma half-life of zafirlukast ranged from approximately8 to 16 hours in both normal subjects and patients with asthma allergy medication. The pharmacokineticsof zafirlukast are approximately linear over the range from 5 mg to 80 mg allergy medication. Steady-stateplasma concentrations of zafirlukast are proportional to the dose and predictablefrom single-dose pharmacokinetic data allergy medication. Accumulation of zafirlukast in the plasmafollowing twice-daily dosing is approximately 45% allergy medication. The pharmacokinetic parameters of zafirlukast 20 mg administered as a singledose to 36 male volunteers are shown with the table below allergy medication. Mean (% Coefficient of Variation) pharmacokinetic
Race: No differences in the pharmacokinetics of zafirlukast due to race havebeen observed allergy medication. Elderly: The apparent oral clearance of zafirlukast decreases with age allergy medication. Inpatients above 65 years of age, there is an approximately 2-3 fold greater Cmax and AUC compared to young adult patients allergy medication. Children: Following administration of a single 20 mg dose of zafirlukast to20 boys and girls between 7 and 11 years of age, and in a second study, to 29boys and girls between 5 and 6 years of age, the following pharmacokinetic parameterswere obtained: Parameter Children age
Zafirlukast disposition was unchanged after multiple dosing (20 mg twice daily)in children and the degree of accumulation in plasma was similar to that observedin adults allergy medication. Hepatic Insufficiency: In a study of patients with hepatic impairment (biopsy-provencirrhosis), there was a reduced clearance of zafirlukast resulting in a 50-60%greater C max and AUC compared to normal subjects allergy medication. Renal Insufficiency: Based on a cross-study comparison, there are no apparentdifferences in the pharmacokinetics of zafirlukast between renally-impairedpatients and normal subjects allergy medication. Drug-Drug Interactions
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Copyright 2005 D-S LTD. |