Emedastine Difumarate

DescriptionEmedastine difumarate, a potent H1-receptor antagonist, was launched in Japan for the treatment of allergic rhinitis and urticaria. Emedastine exerts its antiallergic effect via inhibition of substance P-induced histamine release. It has been demonstrated both in vitro and in vivo that this effect is mediated by the inhibition of Ca2+release from extracellular stores and of Ca2+ influx into mast cells. In a clinical trial with bronchial asthma, emedastine improved asthmatic symptoms in 55.3% of patients.

DescriptionEmedastine is a histamine H1 receptor antagonist (Ki = 1.3 nM). It is selective for histamine H1 over H2 and H3 receptors (Kis = 49 and 12.43 μM, respectively), as well as α1-, α2-, and β1-adrenergic and dopamine D1 and D2 receptors, and the serotonin (5-HT) receptor subtypes 5-HT1 and 5-HT2 at 10 μM. Emedastine inhibits histamine-induced phosphoinositide turnover and intracellular calcium mobilization in primary human conjunctival epithelial cells (HCECs; IC50s = 1.6 and 2.9 nM, respectively). It also inhibits histamine-stimulated secretion of IL-6, IL-8, and GM-CSF by primary HCECs (IC50s = 2.23, 3.42, and 1.50 nM, respectively). Ocular application of emedastine prior to histamine challenge inhibits vascular permeability in guinea pigs. Formulations containing emedastine have been used in the treatment of allergic conjunctivitis.

UsesAntihistaminic, H1-receptor; asthma prophylactic; anti-allergic.

DefinitionChEBI: The fumaric acid salt of emedastine containing two molecules of fumaric acid for each molecule of emedastine. A relatively selective histamine H1 antagonist, it is used for allergic rhinitis, urticaria, and pruritic skin disorders, and in eyedrops for the symptomatic relief of allergic conjuntivitis.