The pharmacokinetics of the active ingredient changes linearly. It depends on the dosage, has a weak individual variability and is practically not different from the indices of cetirizine.
Levocetirizin is absorbed quickly enough by oral administration of drugs. On the degree of absorption, eating does not affect, but at the same time lowers its speed. Peak indices inside the plasma are observed 0.9 hours after drug use in the drug dosage and is 207 ng / ml (for a single dose) and 308 ng / ml (with repeated use of the drug in the amount of 5 mg). The equilibrium values within the serum reach 2 days later.
There is no information on the distribution of drugs inside the tissues of the human body, and beyond that on the passage of matter through the BBB. In the animal testing process, the highest index was observed inside the kidneys with the liver, and the lowest was inside the central nervous system. The distribution volume is 0.4 l / kg, and the synthesis with plasma protein reaches 90%.
In the process of metabolism, approximately 14% of the active component is involved in the body. Oxidation, binding with taurine, and N- together with O-dealkylation are carried out. The latter processes are performed with the help of hemoprotein CYP 3A4, and several hemoprotein isoforms participate in the oxidative processes. The active substance has no effect on the activity of hemoprotein isoenzymes 1A2 and 2C9, and in addition 2C19 with 2D6 and 2E1 with 3A4 at their rates, which exceed the peak level after oral dosage in the amount of 5 mg. Since the metabolic process has a low degree, and the suppressive effect does not increase, the probability of interaction of the active ingredient with other substances is extremely small.
Excretion of drugs is often carried out with the help of actively occurring tubular secretion, and in addition glomerular filtration. The half-life is 7.9 + 1.9 hours, and the total purification rate is 0.63 ml / minute / kg. The substance does not accumulate, completely excreted for 96 hours. Excretion of approximately 85.4% of the drug dosage is performed with urine (unchanged form), and approximately 12.9% is excreted with feces.
In persons with disorders of renal activity (with a KC value of <40 ml / minute), the purification rate of the drug decreases, and the half-life increases (in patients receiving hemodialysis, the overall score is reduced by 80%), so they need to select a suitable dosage regimen. During the standard procedure of hemodialysis (4 hours) only a small part (less than 10%) of the active component is excreted.