Aerius Mechanism of Action

Antihistamine.
Pharmacology: Pharmacodynamics: Desloratadine, the active ingredient in Desloratadine tablets and syrup, is an antihistamine with selective peripheral H₁-receptor antagonist activity.
In addition to antihistamine activity, desloratadine has demonstrated antiallergic activities in in vitro (conducted on human cells) and in vivo studies. These studies have shown that desloratadine can inhibit events in the cascade of allergic inflammation, including: release of inflammatory cytokines including IL-4, IL-6, IL-8, IL-13 from human mast cells/basophils; expression of adhesion molecules such as P-selectin; inhibition of allergic cough in animal models.
Pharmacodynamic Properties: In a clinical program, desloratadine was demonstrated to be safe and efficacious in the treatment of symptoms associated with allergic rhinitis. In addition, the safety and efficacy of desloratadine was demonstrated in the treatment of the symptoms of chronic idiopathic urticaria and other dermatologic disorders.
In a study in which desloratadine was administered at a dose of 45 mg daily (nine times the clinical dose) for ten days, no prolongation of the QTc interval was seen.
Desloratadine does not readily penetrate the central nervous system. At the recommended dose of 5 mg daily for adults and adolescents, there was no excess incidence of somnolence as compared to placebo. Desloratadine given at a single daily dose of 7.5 mg to adults and adolescents did not affect psychomotor performance in clinical studies, nor did a single daily dose of 5 mg to adults affect standard measures of flight performance under simulated flight conditions. Desloratadine has no or negligible influence on the ability to drive and use machines.
No clinically relevant changes in desloratadine plasma concentrations were observed in multiple-dose azithromycin, ketoconazole, erythromycin, fluoxetine or cimetidine interaction trials.
Pharmacokinetics: Desloratadine is well absorbed with maximum concentration achieved after approximately 3 hours; the terminal phase half-life is approximately 27 hours. The degree of accumulation of desloratadine is consistent with its half-life and a once daily dosing frequency. The bioavailability of desloratadine is dose proportional over the range of 5 mg to 20 mg.
Desloratadine is moderately bound (82-88%) to plasma proteins.
Desloratadine is extensively metabolized to 3-hydroxy desloratadine, an active metabolite, which is subsequently glucuronidated. A human mass balance study documented a recovery of approximately 87% of the ¹⁴C-desloratadine dose, which was equally distributed in urine and feces as metabolic products.
The pharmacokinetic profile of desloratadine is comparable in healthy adult volunteers and in healthy geriatric volunteers and no dosage adjustment is required.
In single dose trials of desloratadine tablets (7.5 mg) or syrup (5 mg), there was no effect of food on the disposition of desloratadine. In another study, grapefruit juice had no effect on the disposition of desloratadine.
In single dose, crossover studies of desloratadine, the tablet and syrup formulations were found to be bioequivalent.
Toxicology: Preclinical Studies: Desloratadine is the primary active metabolite of loratadine. Preclinical data with desloratadine reveal no special hazard for humans based on studies of genotoxicity, carcinogenic potential, and toxicity to reproduction.
No significant local irritant effect was noted when desloratadine RediTabs was tested in the hamster cheek pouch buccal irritation assay.