title: Pharmacokinetics and pharmacodynamics of cetirizine in infants and toddlers.
abstract: The pharmacokinetics of the second generation H1-receptor antagonist cetirizine were studied in 15 infants and toddlers (mean +/- SD age, 12.3 +/- 5.4 months) who were treated with a single 0.25 mg/kg dose of cetirizine solution. The infants and toddlers were hospitalized for recurrent respiratory infections or other hypersensitivity-related diseases. Blood samples were collected at 1/2, 1, 11/2, 2, 4, 6, 8, 12, and 24 hours, and a 24-hour urine sample was obtained. A peak plasma level of 390 +/- 135 ng/ml was observed after 2.0 +/- 1.3 hours. The elimination half-life was 3.1 +/- 1.8 hours, the apparent oral body clearance was 2.13 +/- 1.15 ml/min/kg, and the apparent volume of distribution was 0.44 +/- 0.19 L/kg. The excretion of unchanged cetirizine in six complete urinary collections was 62.7% +/- 13.2% of the administered dose. An additional pharmacodynamic study (inhibition of the histamine-induced wheal and flare) was performed in 10 of these infants and toddlers, after the intake of 0.25 mg/kg cetirizine twice a day for at least 4 days. A 90% +/- 12% inhibition of the wheal and a 87% +/- 17% inhibition of the flare were still observed 12 hours after the last intake. The duration of the H1-inhibition by cetirizine at the cutaneous level is thus longer in infants and toddlers than could be inferred from its pharmacokinetics; the level of inhibition at 12 hours was the same as in older age groups.
authors.affiliation: Hospital Bulovka, Prague.
authors.forename: V
authors.initials: V
authors.lastname: Spicák
authors.forename: I
authors.initials: I
authors.lastname: Dab
authors.forename: R
authors.initials: R
authors.lastname: Hulhoven
authors.forename: J P
authors.initials: JP
authors.lastname: Desager
authors.forename: M
authors.initials: M
authors.lastname: Klánová
authors.forename: M
authors.initials: M
authors.lastname: de Longueville
authors.forename: C
authors.initials: C
authors.lastname: Harvengt
mesh_terms: D000284:Administration, Oral; D019540:Area Under Curve; D017332:Cetirizine / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology / Q000652:urine; D005260:Female; D006634:Histamine H1 Antagonists / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology / Q000652:urine; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000378:metabolism* / Q000652:urine; D007223:Infant; D008297:Male; D013997:Time Factors
chemical_list: D006634:Histamine H1 Antagonists; D017332:Cetirizine