Antihistamines considerably modulate the cognitive and psychomotor performance of human volunteers

This research investigated the modulating effects of antihistamines—Loratadine, Fexofenadine, Meclizine, and Chlorpheniramine on cognitive (executive function, memory, attention, emotion regulation), mood, psychomotor performance, and sedation in healthy human volunteers. Twenty healthy volunteers received Loratadine 10-mg, Fexofenadine 120-mg, Meclizine 50-mg, Chlorpheniramine Maleate 4-mg, and Placebo 250-mg starch tablet in a five-way crossover, double-blind study. Following each dose the participants were subjected to take a series of test of cognitive functions and psychomotor performances at defined interval. A certain amount of washout period was also maintained for each drug. The test battery included PennCNP—Full Battery Test, Psychology Experiment Building Language, Stanford Sleepiness Scale, and Brief Mood Introspection Scale. The test results These test results were analyzed by one-way and two-way ANOVAs. In general, antihistamines didn't show any statistically significant deviation from that of placebo. However, slight improvement was observed in word memory test (Both immediate and delayed) by Chlorpheniramine; although it increased the reaction time in visual object learning test. Fexofenadine also increased performance in delayed word memory test. Meclizine showed significant reduction (p < 0.05) of reaction time in line orientation task. The subjects receiving Loratadine reported slightly unpleasant mood then control group. This study will contribute to choose antihistamine rightly maximizing the productivity; minimizing the losses of working hours and daytime in school and workplaces. Right options of antihistamines will make wider flexibility for the people needed sharp motor functioning to work in factory with life-threatening machineries achieving less sedation and psychomotor unimpairment.