Description One of the angiotensin-converting enzyme inhibitors (ACE inhibitors) used for hypertension. It is a prodrug that is hydrolyzed after absorption to its main metabolite cilazaprilat. Indication Cilazapril is an ACE inhibtor class drug used in the treatment of hypertension and heart failure. Mechanism of action Cilazapril is a pyridazine ACE inhibitor. It competes with angiotensin I for binding at the angiotensin-converting enzyme, blocking the conversion of angiotensin I to angiotensin II. As angiotensin II is a vasoconstrictor and a negative feedback mediator for renin activity, lower angiotensin II levels results in a decrease in blood pressure, an increase in renin activity, and stimulation of baroreceptor reflex mechanisms. Kininase II, an enzyme which degrades the vasodilator bradykinin, is identical to ACE and may also be inhibited.