/ Dictionary / Index P phentolamine: Meaning and Definition of Find definitions for: phen•tol•a•mine Pronunciation: (fen-tol'u-mēn", -min), [key] — n. Pharm. an alpha blocker, CHNO, used to reduce hypertensive states caused by a catecholamine excess, as in the treatment of pheochromocytoma. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: phentolamine (Thesaurus) phenoxybenzamine phenyl Related Content Daily Word Quiz: candor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language