Since histamine plays a prominent and diverse role in the pathophysiology of allergic disease, therapeutic intervention is usually focused on blocking the effects of this biogenic amine. Studies investigating the mechanisms underlying the effects of H1 antihistamines have demonstrated that a number of agents in this drug class possess anti-allergic/anti-inflammatory properties, in addition to their antihistaminic properties, which may partly explain the high efficacy of these drugs in the treatment of allergic disease with an underlying inflammatory pathology. However, with some exceptions, the majority of anti-allergic/anti-inflammatory effects observed in vitro are noted at concentrations that are several hundred-fold higher than therapeutic levels and are therefore clinically irrelevant. Additionally, it is clear that the H1 antihistamines differ with regard to their anti-allergic/anti-inflammatory potencies in vitro and in vivo. In this regard, both cetirizine and levocetirizine have been shown to have anti-inflammatory/anti-allergic activities at therapeutically relevant concentrations, in vitro and in vivo. Studies investigating the effect of long-term treatment with cetirizine and levocetirizine have indicated that while cetirizine delays the onset, and, in some cases, prevents the development of asthma in children with atopic dermatitis at high risk of developing asthma, levocetirizine significantly improves the quality of life (QOL) in patients with persistent AR. These findings suggest that prophylactic/long-term treatment with cetirizine and levocetirizine may provide an opportunity to prevent/delay the development of asthma in susceptible individuals and to improve the QOL in patients with persistent AR.
- eosinophil transendothelial migration
- H1 antihistamines
- nuclear factor (NF)-KB