Instruction for use: Zafirlukast

The Latin name of the substance Zafirlukast

Zafirlukastum (genus. Zafirlukasti)

Chemical name

4- (5-Cyclopentyloxycarbonylamino-1-methylindol-3-ylmethyl) -3-methoxy-N-o-tolylsulfonylbenzamide

Gross formula

C₃₁H₃₃N₃O₆S

Pharmacological group:

Prostaglandins, thromboxanes, leukotrienes and their antagonists

The nosological classification (ICD-10)

J45 Asthma: Asthma of physical effort; Asthmatic conditions; Bronchial asthma; Bronchial asthma of light course; Bronchial asthma with difficulty in sputum discharge; Bronchial asthma of severe course; Bronchial asthma physical effort; Hypersecretory asthma; The hormone-dependent form of bronchial asthma; Curbing asthma attacks with bronchial asthma; Non-allergic bronchial asthma; Night Asthma; Exacerbation of bronchial asthma; Attack of bronchial asthma; Endogenous forms of asthma; Night attacks of asthma; Cough with bronchial asthma

CAS Code

107753-78-6

Characteristics of the substance Zafirlukast

White or pale yellow amorphous powder, practically insoluble in water, slightly soluble in methanol and easily soluble in tetrahydrofuran, dimethyl sulfoxide and acetone.

Pharmacology

Pharmacological action - anti-inflammatory, anti-asthmatic, preventive bronchospasm.

Competitively blocks leukotriene receptors and prevents contraction of smooth muscles of the bronchi under the influence of the corresponding leukotrienes - LTC4, LTD4 and LTE4.

After intake, absorbed slowly and not fully enough. Admission with food reduces bioavailability by 40%. Cmax is reached after about 3 hours. The level of equilibrium concentration in the plasma is proportional to the dose and is predicted on the basis of the calculation of pharmacokinetic parameters determined at a single dose. In the systemic circulation circulates in the bound (99%) with albumin form. Penetrates into tissues and organs. T1 / 2 - about 10 hours. Extensively metabolized. Metabolites and unchanged zafirlukast are excreted with breast milk and urine (approximately 10%) and feces (89%). Prevents the action of inflammatory mediators, reduces cellular and noncellular components of inflammation, reduces vascular permeability, edema, eosinophilus influx to the lungs, production of superoxide alveolar macrophages. Improves lung function.

Application of substance Zafirlukast

Bronchial asthma of mild and moderate severity (prevention of seizures and maintenance therapy), incl. With ineffectiveness of beta-stimulants.

Contraindications

Hypersensitivity, liver failure, liver cirrhosis, children under 5 years of age (safety and efficacy not determined).

Application in pregnancy and lactation

When pregnancy is possible, if the expected effect of therapy exceeds the potential risk to the fetus.

The action category for fetus by FDA is B.

At the time of treatment should stop breastfeeding.

Side effects of Zafirlukast

From the nervous system and sensory organs: insomnia, headache, weakness.

From the cardiovascular system and blood (hematopoiesis, hemostasis): rarely - hematomas with bruises, bleeding, incl. Hypermenorrhea, thrombocytopenia; Very rarely - agranulocytosis.

On the part of the intestine: nausea, vomiting, abdominal pain; Rarely symptomatic hepatitis, incl. With hyperbilirubinemia, hyperbilirubinemia without increased hepatic transaminase activity; Very rarely - liver failure and fulminant hepatitis.

Interaction

The concentration of zafirlukast in plasma increases (by a factor of 1.5) acetylsalicylic acid, reduces erythromycin (by 40%) and theophylline (approximately 30%). The combination with warfarin prolongs prothrombin time by 35%. Smoking patients may increase the zafirlukast's clearance by 20%.

Routes of administration

Inside.

Precautions for the substance Zafirlukast

It cannot be used to stop bronchospasm. It is not recommended to appoint if a liver function is impaired.

To achieve the effect, therapy should be permanent, prolonged and continue during exacerbations. A sharp cancellation or reduction in the dose of oral glucocorticoids during the transition to zafirlukast therapy in severe bronchial asthma can cause eosinophilic infiltration with signs of systemic vasculitis (Charge-Strauss syndrome).

The increase in serum transaminase levels is usually transient and occurs asymptomatically, but may be an early sign of hepatotoxicity. In case of clinical signs or symptoms indicating liver dysfunction, it is necessary to investigate the activity of serum transaminases (especially ALT). The decision to stop taking should be taken individually. Patients whose zafirlukast was canceled due to hepatotoxicity, the development of which was not associated with any other cause, re-appointment is contraindicated. When taking concomitantly with warfarin, it is recommended that prothrombin time be monitored.