NCIt definition : A synthetic piperazine with anti-emetic, sedative and histamine H1antagonistic properties.
Meclizine blocks the H1 histamine receptor and prevents the symptoms that are caused
by histamine activity on capillaries, bronchial and gastrointestinal smooth muscles,
including vasodilation, increased capillary permeability, bronchoconstriction, and
spasmodic contraction of gastrointestinal smooth muscles. Meclizine hydrochloride
may exert its antiemetic effects by its anticholinergic actions or due to a direct
effect on the medullary chemoreceptive trigger zone.;