“…3 Most of the orally administered H 1 -antihistamines are available in dosage formulations suitable for administration to children and even to infants; however, only 11 of the 40 H 1 -antihistamines have been studied prospectively in children with regard to their pharmacokinetics and pharmacodynamics. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] These studies have generally been conducted after administration of a single dose, 5-10,12-20 but 3 studies have been performed at steady state, 11,12,20 and in a few studies, a population pharmacokinetic design [21][22][23] has been used. The clinical pharmacology of a few of the first-generation H 1 -antihistamines, such as chlorpheniramine, brompheniramine, diphenhydramine, and hydroxyzine, was investigated after they had been used in children for several decades.…”