Montelukast inhibits cysteinyl airway epithelium leukotriene receptor, thereby having both the ability to inhibit bronchoconstriction due to inhalation of cysteinyl-leukotriene in asthmatic patients. Doses of 5 mg is sufficient for the relief of bronchospasm induced by . Use of montelukast at doses exceeding 10 mg per day taken once, does not increase the efficacy of the drug.
Montelukast causes bronchodilation within 2 hours after ingestion; and can complement the bronchodilation caused by β2 -adrenomimetikami.
Absorption Montelukast is rapidly and almost completely absorbed after oral administration. Admission of ordinary food does not affect the bioavailability and maximum plasma concentration coated tablets and chewable tablets. In adults under fasting coated tablets achieved after 3 hours. Oral bioavailability is 64%. When taken on an empty stomach chewable tablets in adults is achieved in 2 hours. Bioavailability is 73%.
The distribution of Montelukast binds to plasma proteins masteron only cycle more than 99%. The volume of distribution of montelukast averages 8-11 liters. Metabolism Montelukast is extensively metabolised in the liver. When using therapeutic doses concentration montelukast metabolites in plasma at steady state in adults and children is not determined. It is assumed that the montelukast metabolism involved isozymes of cytochrome wherein at therapeutic concentrations montelukast not inhibit isozymes of cytochrome.
Excretion clearance of montelukast in healthy adult average of 45 ml / min. Following oral administration of montelukast, 86% of the amount excreted in the feces within 5 days and less than 0.2% – in the urine, which confirms that the montelukast and its metabolites are excreted almost exclusively with bile. The half-life of montelukast in young healthy adults ranges from 2.7 to 5.5 hours. The pharmacokinetics of montelukast retains substantially linear ingestion of doses above 50 mg. When receiving montelukast in the morning and evening differences pharmacokinetics was observed. When receiving one pill once a day 10 mg coated observed moderate (about 14%) of the active substance accumulation in the plasma.
Pharmacokinetics in different patient populations Gender The pharmacokinetics of montelukast in women and men is similar. Elderly patients When administered 1 time per day coated tablets 10 mg pharmacokinetic profile and bioavailability are similar in elderly and younger patients. Hepatic impairment Patients with hepatic insufficiency light and moderate severity and clinical manifestations of cirrhosis noted slowing down the metabolism of montelukast, accompanied by an increase in the area under the curve “concentration-time» by about 41% after a single dose of the drug at a dose of 10 mg.Excretion of montelukast for these patients is somewhat increased as compared with healthy subjects (mean half-time – 7.4 h). Changes dose of montelukast in patients with hepatic insufficiency, mild to moderate severity is not required. Data on the nature of the pharmacokinetics of montelukast in patients with severe hepatic insufficiency (more than 9 points on a scale Child-Pugh) do not. Race There were no differences in clinically relevant pharmacokinetic effects in patients of different races. Renal Insufficiency Since montelukast and its metabolites are not excreted in the urine, the pharmacokinetics montelukast in patients with renal insufficiency has not been evaluated. Adjusting the dose for this group of patients is required.
Indications for use :
- Prevention and long-term treatment of asthma in adults and children from 6 years, including the prevention of daytime and nighttime symptoms, treatment aspirinchuvstvitelnyh patients with bronchial asthma and prevention of bronchospasm caused by exercise.
- Relief of daytime and nighttime symptoms of seasonal allergic rhinitis (in adults and children 6 years of age) and perennial allergic rhinitis (in adults and children 6 years)
- Hypersensitivity to any component of the drug.
- Children under 6 years of age.
Pregnancy and lactation :
SINGULAIR should be used during masteron only cycle pregnancy and lactation only if the expected benefit to the mother outweighs the potential risk to the fetus or child.
Dosage and administration :
Inside one time per day, regardless of the meal.