Suction: after oral administration cetirizine quickly and well absorbed from the gastrointestinal tract. The maximum level of concentration is determined after about 30-60 minutes.
Eating does not have a significant effect on the amount of absorption, but in this case, the rate of absorption is slightly reduced.
Distribution: Cetirizine binds to blood plasma proteins by about 93%. The value of the volume of the distribution (Vd) is low (0.5 l / kg), the preparation does not penetrate into the cell.
The drug does not penetrate the blood-brain barrier.
Metabolism: Cetirizine is poorly metabolized in the liver with the formation of an inactive metabolite.
At 10-day application in a dose of 10 mg accumulation of the drug is not observed. Excretion: approximately 70% of the kidneys are mostly unchanged. The system clearance is about 54 ml / min.
After a single dose of a single dose, the half-life is about 10 hours. In children aged 2 to 12 years, the half-life is reduced to 5-6 hours.
If the renal function is impaired (creatinine clearance is less than 11-31 ml / min) and hemodialysis patients (creatinine clearance less than 7 ml / min), the half-life period increases by 3 times, the clearance decreases by 70%.
Against the backdrop of chronic diseases and in elderly patients there is an increase in the half-life of 50% and a decrease in clearance by 40%.
Hemodialysis is ineffective.