OBJECTIVE The aim of the studies was to characterize the pharmacokinetics of desloratadine in healthy children and to determine the appropriate dose for paediatric patients 2-11 years old. METHODS Two open-label, single-dose studies were carried out in healthy children between 2-5 (n = 18) and 6-11 years old (n = 18). On day 1, subjects received a single oral dose of desloratadine syrup (1.25 mg for 2-5 year olds or 2.5 mg for 6-11 year olds). Subjects were followed for an additional 4 days during which vital signs were measured daily and blood samples were collected periodically. RESULTS Plasma desloratadine C(max) occurred at a median of 2.0 h after dosing in both age groups. Median values for the younger (2-5 years old) and older (6-11 years old) groups were 2.28 and 2.05 ng ml(-1), respectively. Arithmetic (and harmonic) mean t(1/2) (h) values for each group, respectively, were 16.4 (13.9) and 19.4 (15.8). Exposure to desloratadine was similar in both the younger and older age groups, with a median AUC(last) of 38.8 and 38.2 ng ml(-1) h, respectively. These data were similar to values in adults, who received 5 mg doses of desloratadine. No adverse events or clinically significant abnormal laboratory values were noted in either group. CONCLUSIONS Single doses of desloratadine syrup (1.25 and 2.5 mg) were well tolerated in children 2-5 and 6-11 years old. Desloratadine exposure in children appears to be similar to that observed in adults, in whom efficacy has been established.