NCIt definition : A synthetic, dibenzamine alpha adrenergic antagonist with antihypertensive and vasodilatory
properties. Phenoxybenzamine non-selectively and irreversibly blocks the postsynaptic
alpha-adrenergic receptor in smooth muscle, thereby preventing vasoconstriction, relieving
vasospasms, and decreasing peripheral resistance. Reflex tachycardia may occur and
may be enhanced by blockade of alpha-2 receptors which enhances norepinephrine release.
Phenoxybenzamine is reasonably anticipated to be a human carcinogen.;