Effects of sedative and nonsedative antihistamines on prefrontal activity during verbal fluency task in young children: a near-infrared spectroscopy (NIRS) study

Antagonists of histamine H-1 receptors (antihistamines) are widely used for the treatment of allergic disorders in children. These drugs' sedative effect on brain function, however, has been mostly examined in adults. The objective of this study was to examine the effects of anitihistamines on prefrontal cortex activity in young children using near-infrared spectroscopy (NIRS), a novel brain-imaging method. In 15 healthy children (mean age, 7.7 years), we examined changes of oxygenated hemoglobin concentration in the prefrontal cortex while they performed a verbal fluency task 3 h after taking a sedating antihistamine (ketotifen), nonsedating antihistamine (epinastine), or placebo. Ketotifen significantly impaired behavioral performance and cortical activation at the lateral prefrontal cortex compared with placebo. There were no sedative effects on neural response or behavioral performance after epinastine administration. NIRS revealed that sedating and nonsedating antihistamines exert differential effects on brain hemodynamic response in young children.