Loratadine is rapidly and well absorbed in the gastrointestinal tract. The time to reach the maximum concentration (TmOh) loratadine in blood plasma- 1-1,5 hour, and its active metabolite desloratadine - 1,5 - 3,7 hours. Food intake increases the time (TmOh) in the blood plasma of loratadine and desloratadine for approximately 1 hour, but does not affect the effectiveness of the drug. Maximum concentration (FROMmOh) in the blood plasma of loratadine and desloratadine does not depend on food intake. In patients with chronic kidney disease (CmOh) and the area under the curve "concentration - time" (AUC) loratadine and its active metabolite are increased in comparison with those in patients with normal renal function.The half-life (T1 / 2) of loratadine and its active metabolite does not differ from those in healthy patients. T1 / 2 increases with alcoholic liver damage (depending on the severity of the disease) and does not change in the presence of chronic renal failure.
Loratadine has a high degree (97-99%), and its active metabolite - a moderate degree (73-76%) of binding to plasma proteins.
Loratadine is metabolized in desloratadine with the participation of cytochrome isoenzyme CYP3A4 and to a lesser extent the isoenzyme system CYP2D6. It is excreted through the kidneys (approximately 40% of the ingested dose) and through the intestine (approximately 42% of the ingested dose) for more than 10 days, mainly as conjugated metabolites. Approximately 27% of the ingested dose is excreted through the kidneys within 24 hours after taking the medication. Less than 1% of the active substance is excreted through the kidneys unchanged for 24 hours after taking the drug.
Bioavailability of loratadine and its active metabolite is dose-dependent character.
The pharmacokinetic profiles of loratadine and its active metabolite in adults and elderly healthy volunteers were comparable.
Period T1/2 loratadine is from 3 to 20 hours (an average of 8.4 hours), desloratadine - from 8.8 to 92 hours (an average of 28 hours); in elderly patients, respectively, from 6.7 to 37 hours (an average of 18.2 hours) and from 11 to 38 hours (an average of 17.5 hours). In alcoholic liver damage, the half-life period increases in proportion to the severity of the disease and does not change with chronic renal failure. Conducting hemodialysis in patients with chronic renal failure does not affect the pharmacokinetics of loratadine and its active metabolite.