NCIt definition : A commercial combination preparation, by Wyeth, containing brompheniramine maleate
and phenylpropanolamine hydrochloride, with antihistaminergic and vasoconstrictive
properties. Brompheniramine maleate, a propylamine antihistamine binds to and blocks
H1 receptors thereby preventing the actions of histamine. Phenylpropanolamine hydrochloride
is a decongestant that causes constriction of blood vessels mediated through its alpha-adrenergic
signaling, thereby reducing blood flow and improving nasal air flow. Dimetapp is used
to relieve nasal congestion and to treat rhinitis.;