Desloratadine dose selection in children aged 6 months to 2 years: comparison of population pharmacokinetics between children and adults.

AIMS: The aim of this study was to identify the dose of desloratadine in children aged > or =6 months- < or =2 years that would yield a single-dose target exposure (AUC) comparable with that in adults taking 5 mg desloratadine as syrup. METHODS: In a phase 1, single-dose, open-label, pharmacokinetic study in 58 children aged > or =6 months- <1 year and > or =1 year- < or =2 years were randomly assigned to desloratadine syrup 0.625 mg (1.25 ml) and 1.25 mg (2.5 ml), respectively. Because the volume of blood that could be collected from individual subjects was limited, a population pharmacokinetic approach was used to estimate the pharmacokinetics of desloratadine. Safety was assessed based on results of screening and postdose physical examinations, laboratory safety tests, vital signs, and adverse events. RESULTS: The apparent clearance (CL/F) of desloratadine, population estimate (%CV), in children aged > or =6 months- <1 year was 27.8 l h(-1) (35) and corresponding values in children > or =1 year- < or =2 years was 35.5 l h(-1) (51), compared with 137 l h(-1) (58) for adults. The CL/F ratios (children to adults) indicated that doses of 1 mg for > or =6 months- <1 year and 1.25 mg for > or =1 year- < or =2 years would result in similar systemic exposure to that observed in adults receiving the recommended 5 mg dose. Desloratadine was well tolerated with no safety issues. CONCLUSIONS: Doses of 1.0 and 1.25 mg in children aged > or =6 months- < or =2 years should result in an exposure to desloratadine similar to that of adults receiving doses of 5 mg.