LevoCetirizine coated tablets 5 mg. №20

Description

LevoCetirizine tablets Composition
active substance: levocetirizine;

1 film-coated tablet contains levocetirizine dihydrochloride in terms of 100% substance 5 mg;

excipients: microcrystalline cellulose; lactose monohydrate; anhydrous colloidal silicon dioxide; magnesium stearate; coating: hypromellose; polyethylene glycol 6000; titanium dioxide (E171).

LevoCetirizine tablets Dosage form
Film-coated tablets.

Basic physical and chemical properties: round tablets with a biconvex surface, film-coated white or almost white.

LevoCetirizine tablets Pharmacotherapeutic group
Antihistamines for systemic use. Piperazine derivatives. ATC code R06A E09.

LevoCetirizine tablets Pharmacodynamics
Levocetirizine is the active stable R-enantiomer of cetirizine, which belongs to the group of competitive histamine antagonists. The pharmacological action is due to the blocking of H1-histamine receptors. The affinity for H1-histamine receptors in levocetirizine is 2 times higher than that of cetirizine. Affects the histamine-dependent stage of the development of an allergic reaction, reduces the migration of eosinophils, vascular permeability, and limits the release of inflammatory mediators. It prevents the development and facilitates the course of allergic reactions, has an anti-exudative, antipruritic, anti-inflammatory effect, has almost no anticholinergic and antiserotonin action.

Pharmacokinetics
Pharmacokinetic parameters of levocetirizine have a linear relationship, do not depend on dose and time, and demonstrate low variability between patients. The pharmacokinetic profile with the introduction of a single enantiomer is the same as with the use of cetirizine. Chiral inversion is not observed during absorption or elimination.

Absorption

The drug is rapidly and intensively absorbed after oral administration. The degree of absorption of levocetirizine does not depend on the dose of the drug and does not change with food intake, but the maximum concentration (Cmax) of the drug decreases and reaches its maximum value later. Bioavailability reaches 100%.

In 50% of patients, the effect of the drug develops within 12 minutes after taking a single dose, and in 95% – after 0.5-1 hour. Cmax in blood serum is reached 50 minutes after a single oral administration of a therapeutic dose. Equilibrium concentration in the blood is achieved after two days of taking the drug. Cmax is 270 ng / ml after a single use and 308 ng / ml after repeated use at a dose of 5 mg, respectively.

Distribution

There is no information on the distribution of the drug in human tissues, as well as on the penetration of levocetirizine through the blood-brain barrier. The volume of distribution is 0.4 l / kg. Binding to human blood plasma proteins – 90%.

Biotransformation. In humans, the metabolic rate is less than 14% of the dose and therefore the difference due to genetic polymorphism or concomitant use of enzyme inhibitors is expected to be negligible. Metabolic processes include aromatic oxidation, N- and O-dealkylation, and taurine coupling. Dealkylation primarily occurs with the participation of cytochrome CYP 3A4, while numerous and / or indeterminate CYP isoforms are involved in the aromatic oxidation process. Levocetirizine does not affect the activity of cytochrome isoenzymes 1A2, 2C9, 2C19, 2D6, 2E1, 3A4 at concentrations significantly exceeding the maximum after taking a dose of 5 mg orally. Given the low degree of metabolism and the lack of the ability to inhibit metabolism, the interaction of levocetirizine with other substances (and vice versa) is unlikely.

Excretion

Excretion of levocetirizine occurs in two ways – due to glomerular filtration and active tubular secretion. The half-life of levocetirizine from blood plasma in adults (T1 / 2) is 7.9 + 1.9 hours. T1 / 2 of levocetirizine is shorter in young children. The average apparent total clearance in adults is 0.63 ml / min / kg. Basically, levocetirizine and its metabolites are excreted in the urine (on average, 85.4% of the applied dose of the drug). Only 12.9% of the applied dose of the drug is excreted with feces.