Comparative CNS activities of chlorpheniramine maleate, ebastine, and fexofenadine in Swiss albino mice

Background: Not all second-generation antihistamines were devoid of the central nervous system (CNS) effects such as cognitive and psychomotor impairment. Although these drugs penetrate blood-brain barrier (BBB) to lesser extent, many of them have been found to produce dose-related impairment of CNS functions with interdrug differences present among them. Aim and Objective: This study is aimed to analyze and compare the effects of different antihistamines (first and second generation) on the CNS using Swiss albino mice. Materials and Methods: Twenty-four Swiss albino mice of either sex weighing around 25 - 30 g were randomly divided into six groups with six in each group. Antihistamines such as chlorpheniramine maleate (CPM), ebastine, and fexofenadine were administered to respective groups through oral route. Their effects on CNS were evaluated using rotarod and actophotometer. The data were analyzed using statistical methods. Results: CPM produced significant reduction (P < 0.05) in motor coordination and spontaneous locomotor activity. Ebastine does not have any effect on motor coordination but significant reduction (P < 0.05) in spontaneous locomotor activity. Fexofenadine does not have any effect on motor coordination and spontaneous locomotor activity. Conclusion: We conclude that CPM has significant CNS depressant actions, ebastine has minimal CNS depressant actions, and fexofenadine does not have CNS depressant actions.