NCIt definition : The difumarate salt form of emedastine, a second generation, selective histamine H1
receptor antagonist with anti-allergic activity. Emedastine reversibly and competitively
blocks histamine by binding to H1 receptors, thus blocking its downstream activity.
As a result, this agent interferes with mediator release from mast cells either by
inhibiting calcium ion influx across mast cell/basophil plasma membrane or by inhibiting
intracellular calcium ion release within the cells. In addition, emedastine may also
inhibit the late-phase allergic reaction mediated through leukotrienes or prostaglandins,
or by producing an anti-platelet activating factor effect. Upon ocular administration,
emedastine causes a dose-dependent inhibition of histamine-stimulated vascular permeability
in the conjunctiva. Emedastine does not affect adrenergic, dopamine, or serotonin
receptors.;
Semantic type(s)