The effect of fexofenadine, a newer second-generation antihistaminic, on phenobarbitone sleeping time and its comparison with terfenadine, astemizole and cetirizine in albino rats

Background: The second-generation antihistaminic fexofenadine has been claimed to be superior to terfenadine and cetirizine, in possessing the negligible sedating property and can be safely given to pilots and drivers. Here, it is a study that compares the sedative property of fexofenadine to terfenadine, astemizole, and cetirizine by phenobarbitone induced sleeping time in albino rats. Aims and Objectives: To evaluate the nonsedative antihistaminic action of fexofenadine and comparing it with cetirizine, terfenadine, and astemizole. Materials and Methods: A total of 90 albino rats of either sex weighing 100-200 g were selected and randomly divided into nine equal groups. At 0 h phenobarbitone 40 mg/kg is injected intraperitoneal to the rats. The animals are placed on their backs, and duration of loss of righting reflex is measured. Each rat was pretreated at −1 h with the drugs orally using orogastric tube. The different groups are as follows: Group 1 was given distilled water; Groups 2-9 were given with fexofenadine 20 mg and 40 mg/kg. Terfenadine 20 mg and 40 mg/kg, cetirizine 2 mg and 4 mg/kg, and astemizole 2 mg and 4 mg/kg body weight, respectively, and data are statistically analyzed by unpaired t-test and ANOVA. Results: The mean phenobarbitone sleep time duration of fexofenadine (20 mg and 40 mg) is comparable to placebo and is less sedative. This study shows cetirizine produces longer duration of sleep (P < 0.01) followed by astemizole (P < 0.01), terfenadine, and non-sedative fexofenadine. Conclusion: This study shows fexofenadine produces less sedation at both the lower and higher dose as compared to that of control and other groups. [Natl J Physiol Pharm Pharmacol 2017; 7(4.000): 355-358]