Pharmacokinetics and pharmacodynamics of ebastine in children

Ebastine is a new piperidine-containing, relatively nonsedating second-generation H1-receptor antagonist. In a double-blind, parallel-group study of a single 5 mg or 10 mg dose of ebastine syrup used to treat allergic rhinitis in 20 children aged 6 to 12 years, we tested the hypothesis that the medication would have a duration of action of at least 24 hours. We measured plasma concentrations of carebastine, the pharmacologically active metabolite of ebastine, and the wheals and flares produced by epicutaneous tests with histamine phosphate, 1.0 mg/ml. Ebastine was absorbed well; peak carebastine concentrations occurred approximately 3 hours after dosing. Mean plasma elimination half-life values of carebastine ranged from 10 to 14 hours. The pharmacokinetics of carebastine were linear and dose independent in the dosage range studied. After the 5 or 10 mg dose, there were no significant differences between mean plasma elimination half-life values, mean oral clearance values, or mean apparent volumes of distribution. Mean peak plasma carebastine concentrations and mean areas under the plasma carebastine concentration-time curve after the 10 mg dose were 1.93 and 1.76 times, respectively, the values obtained after the 5 mg dose. Both doses significantly reduced the histamine-induced wheal-and-flare areas for up to 28 hours compared with predose values. The differences in effect between the doses generally were not statistically or clinically significant. No adverse effects were noted. We conclude that ebastine, an effective H1-receptor antagonist with a prompt onset of action and a long duration of action, is suitable for once-daily administration to children.