Desloratadine (DB00967): A Comprehensive Pharmacological and Clinical Monograph

Section 1: Executive Summary

Desloratadine is a second-generation, long-acting, tricyclic antihistamine that serves as a cornerstone in the management of allergic conditions.[1] It is the principal active metabolite of loratadine, a fact that fundamentally shaped its development and clinical positioning.[1] The primary mechanism of action of desloratadine is as a highly potent and selective peripheral histamine H1-receptor antagonist; more specifically, it functions as an inverse agonist, which allows it to reduce basal receptor activity in addition to blocking histamine binding.[5] This peripheral selectivity, a result of its limited ability to penetrate the central nervous system, is the basis for its favorable non-sedating profile, a significant advantage over first-generation antihistamines.[1]

The drug is approved for the symptomatic relief of seasonal allergic rhinitis (SAR), perennial allergic rhinitis (PAR), and chronic idiopathic urticaria (CIU).[5] Its clinical efficacy is well-established, providing rapid and sustained 24-hour relief from a broad spectrum of allergic symptoms, including nasal congestion, which is often refractory to other antihistamines.[7] Beyond its primary antihistaminic activity, desloratadine exhibits broad anti-allergic and anti-inflammatory properties, inhibiting the release of various pro-inflammatory mediators from mast cells and basophils.[7] This multifaceted mechanism contributes to its comprehensive clinical effects.