Quickly absorbed from the gastrointestinal tract, vryamya achieve maximum concentration (TCmOh) after oral administration - about 1 hour.Food does not affect the completeness of absorption (AUC), but lengthens by one hour TCmOh and reduces the maximum concentration (CmOh) by 23%. When taken at a dose of 10 mg once a day for 10 days, the equilibrium concentration of the drug (Css) in plasma is 310 ng / ml and is noted 0.5-1.5 h after administration. The connection with plasma proteins is 93% and does not change with the concentration of cetirizine in the range of 25-1000 ng / ml. The pharmacokinetic parameters of cetirizine change linearly when administered in a dose of 5-60 mg. The volume of distribution is 0.5 l / kg.
In small amounts, it is metabolized in the liver by O-dealkylation to form a pharmacologically inactive metabolite (unlike other H blockers1-gistaminovyh receptors, metabolized in the liver with the participation of the cytochrome P450 system). Citirizine is not cumulated. About 2/3 of the drug is excreted unchanged by the kidneys and about 10% - with calves.
Systemic clearance - 53 ml / min. The half-life (T1/2) in adults - K) h, in children 6-2 years - 6 h, 2-6 years - 5 h, 0.5-2 years - 3.1 h.
In elderly patients T1/2 increases by 50%, systemic clearance is reduced by 40% (decreased kidney function).
In patients with impaired renal function (creatinine clearance below 40 ml / mip) clearance of the drug decreases, and T1/2 elongates (as in patients on hemodialysis, total clearance is reduced by 70% at 0.3 ml / min / kg and T1/2 lengthened 3-fold), which requires a corresponding change in the dosage regimen. Virtually not removed during hemodialysis.
In patients with chronic liver disease (hepatocellular, cholestatic or biliary cirrhosis), an increase in T1/2 by 50% and reduced total clearance of 40% (a correction mode requires only with concomitant reduction in glomerular filtration rate).
Penetrates into breast milk.