Pharmacodynamics<unk>  is a tricyclic antihistamine, which acts as a selective inverse agonist of peripheral histamine H1 receptors. The potency of second generation histamine antagonists is (from strongest to weakest) desloratadine (Ki 0.4 nM) > levocetirizine (Ki 3 nM) > cetirizine (Ki 6 nM) > fexofenadine (Ki 10 nM) > terfenadine ><unk> . However, the onset of action varies significantly and clinical efficacy is not always directly related to only the H1 receptor potency, as concentration of free drug at the receptor must also be considered.<unk>  also shows anti-inflammatory properties independent of H1 receptors. The effect is exhibited through suppression of the NF-κB pathway, and by regulating the release of cytokines and chemokines, thereby regulating the recruitment of inflammatory cells. Pharmacokinetics<unk>  is given orally, is well absorbed from the gastrointestinal tract, and has rapid first-pass hepatic metabolism; it is metabolized by isoenzymes of the cytochrome P450 system, including CYP3A4, CYP2D6, and, to a lesser extent, several others.<unk>  is almost totally (97–99%) bound to plasma proteins. Its metabolite desloratadine, which is largely responsible for the antihistaminergic effects, binds to plasma proteins by 73–76%.<unk> 's peak effect occurs after 1–2 hours, and its biological half life is on average eight hours (range 3 to 20 hours) with desloratadine's half-life being 27 hours (range 9 to 92 hours), accounting for its long-lasting effect. About 40% is excreted as conjugated metabolites into the urine, and a similar amount is excreted into the feces. Traces of unmetabolised<unk>  can be found in the urine. In structure, it is closely related to tricyclic antidepressants, such as imipramine, and is distantly related to the atypical antipsychotic quetiapine.
Loratadine
Desloratadine
Rupatadine
Olopatadine
Roxadustat
Terfenadine
Mibolerone
Ecallantide