H1-receptor antagonists: a critical reappraisal.

This review of second-generation H1-receptor antagonists aims to examine the therapeutic index of the different drugs that are available in light of the new criteria linked to specific and non-specific pharmacological activities.

Blood distribution of levocetirizine, a new non-sedating histamine H1-receptor antagonist, in humans.

The aim of the present study was to determine (1) the extent of levocetirizine binding to human blood cells, plasma and individual plasma proteins; (2) the parameters for levocetirizine binding to individual plasma proteins both at their physiological concentrations and, for human serum albumin (HSA), at a lower saturating concentration; and (3) to simulate levocetirizine distribution in human blood using the information obtained at physiological haematocrit (H) for blood cells and at physiological concentrations for individual plasma proteins. The nature of the main binding sites of HSA, i.e.

[H1 antihistaminics: can we precisely define the characteristics of the ideal molecule?].

The experience of the past twenty years in the field of H1 antihistamines prompts us to consider that these drugs are more dissimilar than has previously been reported in the scientific literature. In fact, the H1 antihistamines that are used in man seem to be effective, even if there are some differences in clinical efficacy. Nevertheless they may have marked differences as far as the following aspects are concerned: their possible binding to various biological targets, their pharmacokinetics, their metabolism and their volume of distribution.

Adhesion molecule profiles in atopic dermatitis vs. allergic contact dermatitis: pharmacological modulation by cetirizine.

Background: Experimental data suggest that there is an imbalance between Th1 and Th2 cells in atopic dermatitis (AD) skin compared to allergic contact dermatitis (ACD). This imbalance (Th2 and Th1 predominance, respectively) implies the production of different cytokines in these two conditions leading to different expression of adhesion molecules on skin endothelial cells.

Objective: The expression of VCAM-1 (IL-4/Th2-dependent) and ICAM-1 (INF-gamma/IL-1) on dermal vessels was compared in six patients with AD and six patients with ACD.

Cetirizine inhibits bradykinin-induced cutaneous wheal and flare in atopic and healthy subjects.

Background: Kinins are vasoactive mediators involved in allergic reactions. When applied on the skin or in the nose, bradykinin (BK) elicits inflammation that is poorly affected by previous H1-blockade. The aim of this study was to compare the possible effect of cetirizine (an H1-antagonist) on wheal and flare responses to BK, histamine, and compound 48/80 in atopic and healthy subjects.