About Fosinopril Phosphonate-containing Angiotensin-Converting Enzyme (ACE) Inhibitor, Antihypertensive. Mechanism of Action of Fosinopril It is a prodrug and converted in to active Fosinoprilat- which is an angiotensin converting enzyme inhibitor prevents the conversion of angiotensin-1 to angiotensin-2 and abolishes the pressor actions of angiotensin. It decreases aldosterone secretion, sodium and water retention, and total peripheral resistance, leads to fall in BP. The arterioles dilate and the compliance of larger arteries is increased. Both systolic and diastolic BP is lowered. The drug does not compromise renal, cerebral, and coronary blood flow. The drug also increases plasma kinin levels and potentiate the hypotensive action of exogenously administered bradykinin. It is used for treatment of systolic heart failure, because it improves symptoms, decrease mortality and reduce ventricular hypertrophy.