Main unwanted side effect of sedating antihistamines Onlinesex chat pilipino
H-antihistamines, which are not structurally related to histamine, do not antagonize the binding of histamine but bind to different sites on the receptor to produce the opposite effect.
While desloratadine is less efficacious, it has the advantages of rarely causing somnolence and having a long duration of action.
Although some of these attributes may be predicted from preclinical and pharmacokinetic studies, it is only in the clinical environment that they may be definitively established.
The efficacy of an H-receptors is determined in preclinical studies.
For example, in inflammation the p H of the tissues is reduced from 7.4 to 5.8, leading to a 2-to 5-fold increase in the affinity of fexofenadine and levocetirizine for H-receptors but no change in the affinity of desloratadine.
As shown in Figure 2, histamine receptors are situated on the cellular membranes of cells, including vascular and airways smooth muscle, mucous glands, and sensory nerves, all of which are surrounded by the extracellular fluid.