Лоратадин

Описание

Loratadine is a non-sedating antihistamine indicated for use in allergic rhinitis and chronic urticaria. Its major advantage over other non-sedating antihistamines such as astemizole and terfenadine is its very fast onset of action. Loratadine is claimed not to cross the blood-brain barrier.

Химические свойства

White Crystalline Solid

Использование

Loratadine, is used as a peripheral histamine H1 receptor agonist. It is also used as an orally active antiallergic agent. It is an important raw material and intermediate used in Organic Synthesis, Pharmaceuticals, Agrochemicals and Dyestuff.

Показания

Loratadine (Claritin) is a long-acting, potent peripheral H1 blocker with minimal sedative effects. It does not appear to have the same adverse cardiac effects as the other nonsedating H1 antihistamines. It is indicated for allergic rhinitis and chronic urticaria.

Общее описание

Loratadine, 4-(8-chloro-5,6-dihydro-11Hbenzo[5,6]-cyclohepta[1,2-b]pyridin-l 1-ylidene-1-carboxylic acid ethyl ester, is a white to off-white powder insoluble in water but very soluble in acetone, alcohols, and chloroform. Loratadine is structurally related to the antihistamines azatadine and cyproheptadine, and to some tricyclic antidepressants. It differs from azatadine, in that a neutral carbamate group has replaced the basic tertiary amino moiety, and a phenyl ring has been substituted with a chlorine atom. Loratadine is a selective peripheral H1-antihistamine with a receptor-binding profile like that of the other members of this series, except that it has more antiserotonergic activity. Thus, it produces no substantial CNS or autonomic side effects or cardiac toxicity.
Loratadine displays potency comparable with that of astemizole and greater than that of terfenadine. Loratadine is indicated for the relief of nasal and nonnasal symptoms of seasonal allergic rhinitis. In the presence of a CYP3A4 inhibitor ketoconazole, loratadine is metabolized to descarboethoxyloratadine predominantly by CYP2D6.

Биологическая активность

Peripheral histamine H 1 receptor antagonist (K i = 35 nM); devoid of central effects. Orally active antiallergic agent.

Клиническое использование

Loratadine is related to the first-generation tricyclic antihistamines and to antidepressants. It is nonsedating, and neither it nor its major metabolite, desloratadine (descarboethoxyloratadine), is associated with the potentially cardiotoxic effects reported for terfenadine and astemizole. On chronic dosing, the AUC (plasma concentration–time curve) for the metabolite is greater than that for the parent drug, and its half-life is longer.