UREX (methenamine hippurate) is a urinary tract antiseptic drug. Each white, scored UREX tablet contains methenamine hippurate 1 g (see HOW SUPPLIED). UREX (methenamine hippurate) tablets also contain: magnesium stearate, povidone and saccharin sodium. Chemically, methenamine hippurate is the hippuric acid salt of methenamine (hexamethylenetetramine).