New non sedating antihistamines Adult chat picture sharing
In rats, it was shown for several 1st and 2nd generation antihistamines that receptor binding continues to increase with the dose until full receptor saturation occurs2.
Thus the 'non-sedating' title of the 2nd generation antihistamines refers to a low tendency to diminish CNS arousal when taken in therapeutic doses.
The dichotomy between 1st and 2nd generation antihistamines was introduced in 1983 at about the time of the European registration of two drugs: terfenadine and astemizole.
The distinction was drawn by the drugs' manufactures to indicate a major pharmacological difference between these drugs and their predecessors.
However there is no reason to believe that all 'non- sedating' antihistamines possess exactly the same low tendency to cross the blood brain barrier.
The study by Mann et al 3 nicely illustrates this point of view.
Their prescription-event monitoring study demonstrated that 2nd generation antihistamines differ in their potential to produce sedation.The odds ratios for the incidence of sedation were 0.63 for fexofenadine, 2.79 for acrivastine and 3.53 for cetirizine compared with loratadine.