title: The pharmacokinetics and pharmacodynamics of terfenadine in children.
abstract: The pharmacokinetics and pharmacodynamics of terfenadine were studied in 13 children with allergic rhinitis, mean age 7.45 +/- 0.54 SEM years. Serum concentrations of the active carboxylic acid metabolite of terfenadine (terfenadine metabolite I) were measured before and hourly for 8 hours after administration of a single dose of terfenadine suspension. The mean maximum serum concentration of terfenadine metabolite I, 242 +/- 28 ng/ml, occurred at 2.3 +/- 0.2 hours; the mean serum half-life value was 2.0 +/- 0.1 hours. Wheals and flares after epicutaneous tests with histamine phosphate, 1.0 mg/ml and 0.2 mg/ml, were significantly suppressed from 1 to 8 hours after the terfenadine dose compared to predose values. Maximum wheal suppression occurred at from 3 to 6 hours. Itching was completely suppressed for 8 hours. No serious adverse effects occurred. Terfenadine in children appears to be well absorbed, and its carboxylic acid metabolite has a short serum elimination half-life. The duration of its suppressive effect on the histamine-induced wheal and flare greatly exceeds that expected from consideration of serum terfenadine metabolite I concentrations.
mesh_terms: D001559:Benzhydryl Compounds / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006207:Half-Life; D006634:Histamine H1 Antagonists / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000494:pharmacology; D006801:Humans; D008297:Male; D012221:Rhinitis, Allergic, Perennial / Q000097:blood* / Q000276:immunology; D012882:Skin Tests; D016593:Terfenadine
chemical_list: D001559:Benzhydryl Compounds; D006634:Histamine H1 Antagonists; D016593:Terfenadine