The pharmaceutical parameters of cetyrizin change linearly.
Suction. After taking it inside, the drug is quickly and completely absorbed from the LCD. Eating does not affect the completeness of absorption, although its speed decreases. In adults, after a single medication in therapeutic dose Cmax in blood plasma is 300 ng / ml and is achieved through (1 ± 0.5) h.
Distribution. Cetirisin on (93 ± 0.3)% binds to blood plasma proteins. Vd is 0.5 l / kg. When taking the drug at a dose of 10 mg for 10 days, cetyrizin cumulation is not observed.
Metabolism. In small quantities, it is metabolized in the body by O-dealkylation (unlike other antagonists H1-histamines that are metabolized in the liver using a cytochrome system) with the formation of pharmacologically inactive metabolite.
The conclusion. In adults T1/2 is approximately 10 hours; in children from 6 to 12 years old - 6 hours, from 2 to 6 years old - 5 hours, from 6 months to 2 years old - 3.1 hours. Approximately 2/3 of the accepted dose of the drug is withdrawn by the kidneys unchanged.
In elderly patients and patients with chronic liver diseases with a single medication at a dose of 10 mg T1/2 increases by about 50%, and system clearance is reduced by 40%.
In patients with renal failure of mild severity (Cl creatinine> 40 ml / min), pharmacokinetic parameters are similar to those in patients with normal kidney function.
In patients with moderate renal failure and in patients undergoing hemodialysis (Cl creatinine <7 ml / min), when taking the drug inward at a dose of 10 mg T1/2 lengthens 3 times, and the total clearance is reduced by 70% relative to these indicators in patients with normal kidney function, which requires a corresponding change in the dosing mode.
Cetirisin is practically not removed from the body during hemodialysis.
The pharmaceutical parameters of cetyrizin when used in doses of 5 to 60 mg change linearly.
Suction. Cmax in blood plasma is achieved through (1 ± 0.5) h and is 300 ng / ml.
Various pharmacokinetic parameters, such as Cmax in blood plasma and AUC are homogeneous.
Eating does not affect the completeness of cetyrizin absorption, although its speed decreases. The bioavailability of various dosage forms of cetyrizin (rathering, capsules, tablets) is comparable.
Distribution. Cetirisin on (93 ± 0.3)% binds to blood plasma proteins.
Vd is 0.5 l / kg. Cetirisin does not affect the binding of warfarin with proteins.
Metabolism. Cetirisin is not exposed to extensive primary metabolism.
The conclusion. T1/2 is approximately 10 hours.
When taking the drug in a daily dose of 10 mg for 10 days, cetyrizin cumulation was not observed.
Approximately 2/3 of the accepted dose of the drug is withdrawn with urine in an unchanged form.
Elderly patients. In 16 elderly patients with a single medication in a dose of 10 mg T1/2 was 50% higher, and clearance was 40% lower compared to patients of not old age. The decrease in cetirizin clearance in older patients is probably due to a decrease in the function of the kidneys in this category of patients.
Renal failure. In patients with renal failure of mild severity (Cl creatinine> 40 ml / min), pharmacokinetic parameters are similar to those in healthy volunteers with normal kidney function.
In patients with moderate renal failure and in patients undergoing hemodialysis (Cl creatinine <7 ml / min), when taking the drug inward at a dose of 10 mg T1/2 lengthens 3 times, and the overall clearance is reduced by 70% relative to healthy volunteers with normal kidney function.
For patients with renal failure of moderate or severe degree, a corresponding change in the metering mode is required (see. “Method of application and doses”).
Cetirisin is poorly removed from the body during hemodialysis.
Pediatric failure. In patients with chronic liver diseases (hepatocellular, cholestatic and biliar cirrhosis) with a single medication at a dose of 10 or 20 mg T1/2 increases by about 50%, and clearance is reduced by 40% compared to healthy entities. Correction of the dose is necessary only if the patient with liver failure also has concomitant renal failure.
Children. T1/2 in children from 6 to 12 years old it is 6 hours, from 2 to 6 years old - 5 hours, from 6 months to 2 years old - reduced to 3.1 hours.
