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diphenhydramine hydrochloride 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. Check for active clinical trials or closed clinical trials using this agent. (NCI Thesaurus)
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US brand names: | ![](https://webarchive.library.unt.edu/eot2008/20081005075230im_/http://www.nci.nih.gov/images/spacer.gif) | Benadryl SK-Diphenhydramine | | ![](https://webarchive.library.unt.edu/eot2008/20081005075230im_/http://www.nci.nih.gov/images/spacer.gif) | Foreign brand names: | ![](https://webarchive.library.unt.edu/eot2008/20081005075230im_/http://www.nci.nih.gov/images/spacer.gif) | Bendylate Eldadryl | | ![](https://webarchive.library.unt.edu/eot2008/20081005075230im_/http://www.nci.nih.gov/images/spacer.gif) |
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