Indications
Desloratadine is indicated for the alleviation of symptoms associated with seasonal allergic rhinitis and perennial allergic rhinitis, providing·h as nasal cong·he symptomatic treatment of pruritus and urticaria, particularly those associated with chronic idiopathic urticaria, including·he reduction of itching·he prevention of hives.
Pharmacodynamics
Desloratadine is classified as a long·h1-receptor antagonist with selective and peripheral activity. It functions by blocking·histamine from binding·h1 receptor, thereby inhibiting·he subsequent release of chemicals responsible for allergic symptoms. Unlike many antihistamines, Desloratadine does not penetrate the brain-blood barrier, effectively minimizing·he risk of drowsiness as a side effect.
Absorption
When administered orally, Desloratadine demonstrates efficient absorption characteristics. Upon daily administration of a 5 mg tablet over ten days, Desloratadine reaches a peak plasma concentration (Tmax) of approximately 3 hours, with a mean steady-state Cmax of 4 ng·hr/mL. Comparable pharmacokinetic profiles are observed when delivered as a 10 mL oral solution containing·he active ing·he presence of food does not influence the absorption of Desloratadine.
Metabolism
Desloratadine undergoes hepatic metabolism, converting·hydroxydesloratadine. This metabolite is further processed through glucuronidation, a pathway facilitating·his metabolic transformation plays a crucial role in the drug's efficacy and duration of action.
Mechanism of Action
Desloratadine functions by competing with free histamine for H1-receptor binding sites located in the gastrointestinal tract, uterus, large blood vessels, and bronchial smooth muscle. Through this competitive inhibition, Desloratadine effectively blocks the action of endogenous histamine, providing temporary relief from symptoms such as nasal congestion and watery eyes that are typically induced by histamine.
