Diphenhydramine Hydrochloride

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** The hydrochloride salt form of diphenhydramine, an ethanolamine and first-generation histamine antagonist with anti-allergic activity. Diphenhydramine hydrochloride competitively blocks H1receptors, thereby preventing the actions of histamine on bronchial smooth muscle, capillaries, and gastrointestinal (GI) smooth muscle. This prevents histamine-induced bronchoconstriction, vasodilation, increased capillary permeability, and GI smooth muscle spasms.

**Synonyms:** - Benadryl - Benadryl - Bendylate - Bendylate - DIPHENHYDRAMINE HYDROCHLORIDE - Diphenhydramine hydrochloride - Diphenhydramine.HCl - Eldadryl - Eldadryl - SK-Diphenhydramine - SK-Diphenhydramine