Hydroxyzine Hydrochloride

**Semantic type:** Pharmacologic Substance

**Definition:** The hydrochloride salt form of hydroxyzine, a piperazine histamine H1-receptor antagonist with anti-allergic, antispasmodic, sedative, anti-emetic and anti-anxiety properties. Hydroxyzine hydrochloride blocks the H1 histamine receptor and prevents the symptoms that are caused by histamine activity on capillaries, bronchial smooth muscle, and gastrointestinal smooth muscle, including vasodilatation, increased capillary permeability, bronchoconstriction, and spasmodic contraction of gastrointestinal smooth muscle. In addition, hydroxyzine hydrochloride crosses the blood-brain barrier and acts on the histamine H1-receptors in the central nervous system. (NCI05)

**Synonyms:** - 1-(p-Chlorobenzhydryl)-4-(2-(2-hydroxyethoxy)ethyl)diethylenediamine Hydrochloride - Anxanil - Atarax - HYDROXYZINE HYDROCHLORIDE - Hyzine-50